Bilateral Hip AVN Xray




Non-traumatic or traumatic condition of femoral head with bone death




20 - 50 yo (average 38)

- M: F 4:1




70-80% with AVN will progress within 1 year







- > 4000 ml / week



- > 20mg / day

- often bilateral



- incidence of hypercoagulability

- alcohol probably related to most idiopathic



- displaced subcapital

- dislocation


Gout, Gaucher's

Rheumatoid, radiation

Infection, increased lipids, inflamm (arteritis)

Pancreatitis, pregnancy

SLE, Sickle cell, smoking

CRF, chemotherapy, Caisson




Fat Embolism Theory


Alteration in lipid metabolism

- fat emboli have been demonstrated in subchondral arterioles in femoral head in patients on steroids

- steroids increases fat stores in liver, bm, blood


Lipocyte hypertrophy theory


Increased bone marrow fat stores & lipocyte hypertrophy 

- increased bone marrow pressure

- leads to decreased blood flow

- lipid lowering drugs shown to improve femoral head blood flow

- may represent a compartment syndrome

- Gaucher, leukaemia


Accumulative stress theory


Kenzora & Glimcher

- suggests AVN multifactorial

- accumulative insult

- eg alcohol, steroids, illness


Multiple hit theory


Either have cumulative dose response reaching threshold for AVN eg many different insults 


Susceptible individual exposed to aetiological factor

- attempts to explain why small ETOH or steroids causes AVN in some but not others


Vascular & Non Vascular Theories


1. Vascular 


A. Inside vessel


Fat Emboli in Alcohol & Steroids


?Nitrogen in Caisson Disease

Sickle Cell = Venous occlusion

Hyperlipidaemia of other causes


B. Vessel Wall


Traumatic disruption - 26 % of subcapital fractures


Arteriopathy & haemorrhage


C. Outside vessel via intraosseous pressure


Fat cell hypertrophy 

- steroids / alcohol 

- "Starling" effect

- increased intraosseous hypertension in fixed space


Oedematous marrow

- Gaucher cells / leukaemia / DXRT / gout / CRF


2.   Non Vascular


Chemotherapy / Radiotherapy  

- osteocyte death




Cumulative Risk

- dose x time cortisol ? 2000mg



- incidence 3-25%

- onset ~ 6/12 - 3 years

- usually bilateral & multiple sites



- steroids cause osteoblastic stem cells to become fat cells 



- MOA uncertain

- ? 2° to both intraosseous HTN & altered fat metabolism with fat emboli

- often affects other sites


Caisson Disease

- 2° N2 in blood vessels & extravascular

- compressed air workers ~ 20%

- divers ~ 5% in army

- humeral head > femoral




Starts in Anterior / Superior / Lateral head 

- wedge shaped area



- regions of bone reabsorption

- fibrous regions on microscopy


Crescent Sign 

- subchondral collapse of the necrotic segment

- separation of subchondral plate from necrotic cancellous bone



- accumulated stress fracture

- 2° OA results

- NHx is progression to collapse in >90%


Dead bone is resorbed prior to new bone formation  

- resorption begins just after vascular invasion

- resorption continues until majority of necrotic haversian bone is removed, but almost none of interlamellar bone removed

- only once this has occurred do osteoblasts begin forming new haversian bone


It is at the revascularisation phase when the head is at its most susceptible




1. Necrosis


2. Inflammation / Revascularisation / Resorption


3. Repair - osteoblasts, new bone on dead trabeculae 


4. Remodelling


Four Causes Sclerosis


1.  Relative osteopenia in surrounding bone

2.  Marrow saponification

3.  Microfracture

4.  New bone apposition


Classification Ficat 1985


Stage 0 


"Silent contralateral hip" 

- preclinical - non painful

- X-ray normal

- MRI = double Line positive on T2

- cold scan


Stage I 


Clinically painful

- normal X-ray 

- increased uptake on scan

- MRI positive


Hip AVN MRI Anterior headHip AVN MRI T1


Stage II


Diffuse porosis with

- sclerosis 

- cystic areas of reabsorption


HipAVN Type 2Hip AVN Type 2 APHip AVN Type 2 Lateral



- Crescenteric sign / subchondral fracture


Stage III


Collapse / Flattening

- sequestrum

- preserved joint space

- typically anterolateral head


Hip AVN Type 3


Stage IV


OA superimposed on a deformed head


Hip AVN Type IIIHip AVN Type 3Hip AVN Type IV




1.  Divided extent of head involved

- most important prognosticator


A = Mild <15%

B = Moderate 15-30% 

C = Severe >30%


2.  Stages


Stage 1: normal xray

Stage 2: sclerosis

Stage 3: crescent sign / subchondral collapse

Stage 4: flattening of femoral head

Stage 5 & 6: OA


Kerboul Combined Necrotic Angle 


JBJS B 1974


Guide to outcome 

- AP + Lat Necrotic Wedge Angle 

- > 200° = Poor




Limited place

- can eiagnose early collapse & flattening

- 1/3 of Grade II upgraded to grade III by CT




Te Scan


Sensitivity 80%

- non-specific

- most useful to investigate if head vascular after subcapital fracture




Sensitivity 100% in one series

- may take up to 7 days to show 


Low T1 / High T2


T2 Double Line Sign


Hip AVN MRI T2 Double Line Sign


Two lines virtually diagnostic of AVN

- outer line / low signal intensity

- inner line / hihg signal intensity / hypervascular granulation tissue


DDx Transient osteoporosis of the Hip



- third trimester pregnancy



- oedema into metaphysis or neck

- suspect AVN if collapse 


Natural History AVN


Asymptomatic Hip


Mont et al JBJS Am 2010

- systemic review of asymptomatic hips

- 59% progressed to symptoms or collapse

- small medial lesions progressed to collapse < 10%

- sickle cell high risk, SLE low risk


Hernigou JBJS Am 2006

- 91% asymptomatic sickle cell AVN became symptomatic

- 77% collapse


Management Summary


Stage 0


Natural history mixed

- depends on size of lesion and diagnosis

- treat if becomes asymptomatic

- may benefit from bisphosphonates


Stage 1 / Normal X-ray, abnormal MRI


Forage: 80% G/E



Stage 2 / Abnormal X-ray with cysts and sclerosis


A:  As for Stage I


B:  Vascularized fibula graft: 80% 


Stage 3 / Collapse / Crescent sign


A:  Forage: 20% G/E


B:  Osteotomy:  80% G/E (CAN < 200o)


C:  Trapdoor and BG 80%


D:  Vascularised fibula graft: 80% G/E


E:  Limited Femoral Head Resurfacing


Stage 4


A:  Conventional THR


B:  Resurfacing 


C:  Arthrodesis 

- only if unilateral (<50%)


Non operative Management






Hyperbaric oxygen





- inhibit osteoclast absorption

- limit head collapse




Lai et al JBJS Am 2005

- RCT of aledronate v control in non traumatic AVN

- 2/29 in treatment group collapsed, 1 had THR

- 19/25 in control group collapsed, 16 had THR




Extracorporeal shock wave therapy




Wang et al JBJS Am 2005

- RCT of ECSW v forage & bone graft

- 80% improvement and 10% unchanged in ECSW

- 29% improved and 36% unchanged in surgical group


Hyperbaric Oxygen




Camporesi J Arthroplasty 2010

- RCT of stage II AVN treated with hyperbaric O2 or air

- all HBO patients were pain free and non required THR

- 7/9 HBO showed radiographic healing


Operative Management




Femoral head preserving / pre-collapse

- forage

- vascularised bone graft

- non vascularised bone graft


Salvage / post collapse

- osteotomy

- limited resurfacing / femoral resurfacing



Femoral Head Preserving


Forage / Core Decompression




Ficat / Arlet

- initially used for diagnosis of HTN

- then used as treatment

- noticed pain relief of & cessation of progress



- decompress intraosseous hypertension

- promotion of vascular ingrowth

- promotion creeping substitution




Provides good pain relief

Does it prevent collapse / alter NHx?

Related to stage and size of lesion




Hip Forage Intraoperative


Take 6-8 mm core 

- insert guide wire under II

- ensure entry above LT

- 5mm from subchondral bone

- use DHS triple reamer

- NWB 6/52


Results Pain Relief


Stulberg Clin Orthop 1991

- prospective randomised study

- forage vs nonoperative management

- forage 70% success Ficat stage I to III in Harris Hip scores

- nonoperative success 20% Stage I / 0% Stage II / 10% stage III


Results NHx


Steinberg J Arthroplasty 1998

- patients post core decompression

- < 15% head involvement stage IA & IIA / only 20% needed THR

- > 15% head involvement stage IB & IIB / 40% needed THR


Khoo et al JBJS Br 1995

- RCT non operative v core decompression

- excellent pain relief in decompression group

- 80% developed femoral head collapse in both groups


Vascularised Cortical Bone Grafts



- core decompression and removal necrotic bone

- support of subchondral bone with vascularised fibular graft

- revascularisation

- callous formation / osteoinduction



- approach between TFL and G med

- reamer inserted

- packed with cancellous bone

- fibula segment harvested with peroneal artery and vein

- stabilised with K wire

- anastomosed to LCF

- abutting subchondral bone




Scully et al JBJS Am 1998

- stage III 

- 81% 4 year survival vascularised fibula graft

- 21% 4 year survival core decompression


Berend et al JBJS Am 2003

- stage III disease

- failure with THR as end point

- 64.5% 5 year survival


Non vascularised bone graft 




1.  Cortical strut graft


2.  Lightbulb procedure

- head neck junction

- cancellous bone graft


3.  Cartilage trapdoor 

- evacuate necrotic bone

- pack with cancellous bone




Wang Int Orthop 2010

- trapdoor technique

- excellent or good results in 90 - 100% stage IIA or IIB








Aim is to prevent collapse 

- move the avascular segment away from weightbearing area 

- also decompress intraosseous HTN

- must have sufficient intact femoral head to weight bear upon




Stage III 

CNA <200°

Young patient 

Not on steroids




Stage III with total head involvement

Stage IV





CT / MRI  / XR to decide osteotomy direction



- anterolateral AVN 

- undergoes a valgus flexion intertrochanteric osteotomy




Ha et al JBJS Am 2011

- 113 hips followed up for 4 years

- secondary collapse in 24%, THR required in 12%

- age > 40, stage III, CNA > 2000 and BMI > 24 poor prognostic factors


Limited Resurfacing Arthroplasty




Restores spericity to femoral head

- limits FAI which may cause progression to OA

- need to have limited acetabular damage at time of surgery




Mont et al J Arthroplasty 2001

- 30 patients treated after intra-operative inspection acetabulum

- all stage III or IV

- 90% 7 year survival






Femoral resurfacing only

- again need good acetabular cartilage

- not as predictable pain relief




Hungerford et al JBJS Am 1998

- 30 patients stage III or IV

- 61% G/E at 10 years

- remainder needed conversion to THR

- suggested good intermediate option in young patient






? Failure rate higher than in age matched OA patients

- also worse if caused by ethanol / steroids




Ortiguera et al J Arthroplasty 1999

- age matched AVN and OA

- 178 patients in each group

- follow up 17 years

- no difference patients over 50

- < 50 significant increased risk aseptic loosening


Australian Joint Registry 

- 7 years

- THR Revision rate 5% (4% OA)

- resurfacing 6% (4% OA)



Acetabular Fractures




Unusual anatomic convergence of ilium, pubis and ischium

- covered entirely by hyaline cartilage

- except at acetabular fossa, which is the site of attachment of the ligamentum teres

- deepened by peripheral fibrocartilage labrum


2 column theory (Letournel and Judet)


Anterior Column 

- superior pubic ramus

- anterior acetabular wall, anterior dome

- anterior iliac spines and anterior ilium


Acetabulum Anterior ColumnPelvis Anterior Column


Posterior Column 

- ischium

- posterior acetabular wall, posterior dome

- posterior ilium


Acetabulum Posterior ColumnCT Pelvis Posterior Column


Quadrangular Plate


CT Quadrangular Plate




Axial load applied through femur

- type of fracture depends on position of femur at time of injury

- IR - posterior column

- ER - anterior column




Resuscitation EMST


Detailed neurological exam

- sciatic nerve damaged in 20% cases with posterior wall or column injury 

- usually peroneal division


Careful soft tissue evaluation

- closed degloving injury

- 'Morel-Lavallee' lesion

- the serosanginous fluid collection can be culture positive in up to 30%


X-ray / 5 standard views


AP / Six X-ray Landmarks


Acetabulum Anterior and Posterior WallsAcetabulum Ilioischial Iliopectineal LinesAcetabulum Roof and Teardrop


1.  Iliopectineal line 

- along pelvic brim to pubic symphysis

- anterior column


2.  Ilioischial Line 

- pelvic brim to ischial tuberosity

- posterior column

- formed by posterior 4/5 of quadrilateral surface ilium


3.  The Teardrop 

- lateral: subchondral bone condensation at anterior margin of cotyloid fossa 

- medial:  anterior flat part of quadrilateral surface of iliac bone


4.  Roof of acetabulum


5.  Anterior rim of acetabulum

- semilunar


6.  Post rim of acetabulum


Judet views  / 45o obliques


Internal Oblique / Obturator Oblique

- affected side rotated forward

- anterior column + posterior wall


Judet ViewJudet View Acetabular FractureAcetabular Fracture Judet View


External Oblique / Iliac Oblique

- unaffected side rotated forward

- posterior column + anterior wall


Inlet view / Outlet view


Indicated for pelvic fractures usually


Pelvic Fracture Inlet ViewPelvic Fracture Outlet View






1-2 mm sections


CT reconstruction

- remove head to view acetabulum

- beware volume averaging

- used to guide surgery


Acetabular Fracture CT Reconstruction




Loose bodies

Femoral head fractures

Subtle subluxation

Articular steps

Roof arc measurement


Letournel Classification


5 Elementary

5 Complex


Elementary / One primary fracture line


1.  Posterior Wall

- often associated with posterior dislocation

- may be in one or many pieces

- may have marginal impaction fracture


Acetabular Fracture Posterior WallAcetabulum Posterior Wall Fracture


2.  Posterior Column

- whole posterior column separated in one piece

- fracture greater sciatic notch

- through inferior acetabulum

- into obturator foramen

- through inferior pubic rami


Posterior Column Fracture 1Posterior Column Fracture Xray 2Posterior Column Fracture Xray 3


Acetabular Fracture Posterior ColumnAcetabular Fracture Posterior Column 2


3.  Anterior Wall


Acetabular Fracture Anterior Wall


4.  Anterior Column

- from ilium above ASIS

- through inferior acetabulum  

- across obturator foramen

- out through inferior rami


Acetabular Fracture Anterior WallAcetabular Fracture Anterior Column


5.  Transverse

- from greater sciatic notch to AIIS

- obturator foramen not fractured


Pelvic Fracture TransverseAcetabular Fracture Transverse CT1Acetabular Fracture Transverse


High - above acetabulum 

Low - through acetabulum


Complex / More than one primary fracture line


1.  Posterior column & posterior wall


2.  Transverse & posterior wall


3.  T-shaped

- transverse through acetabulum

- inferior fracture line to obturator foramen


4.  Anterior & posterior hemi-transverse


5.  Both column

- Y Shaped transverse above acetabulum


Acetabular Fracture Both Columns 1Acetabular Fracture 2 Column


Acetabular Fracture 3D CT Anterior ColumnAcetabular Fracture 3D CT Posterior Column


Determinants of outcome


1.  Fracture displacement

- < 2mm articular step


Acetabular Fracture DisplacedAcetabular Fracture Undisplaced


2.  Fracture location


Early onset of arthritis and poor clinical results correlate with 

- displacement present at the time of union within the weight bearing dome

- any roof arc measurement less than 45°

- a broken CT subchondral ring


A.  Matta roof arc measurements


Describe location of fracture lines in relation to roof of acetabulum

- integrity of acetabular roof

- must be no hip subluxation


3 roof arc measurements

- AP, 2 Judet's views

- vertical line to centre of head

- line to where fracture enters joint

- the larger the arc, the further the fracture from the roof

- 10o - fracture in roof

- 900 - low fracture


Weight bearing dome is intact if angle > 45o on all 3 views


B.  CT subchondral arc

- 10 mm below subchondral bone of roof

- similar to xray roof arc measurements


Acetabular Fractures CT Subchondral arc 1Acetabular Fracture CT Subchondral Arc 2


3.  Stability / Concentric reduction



- incongruency between the head and the roof

- poor clinical results are obtained in more than 50% of fractures in which the head is subluxed  

- may also have an element of dynamic instability, with certain posterior wall fractures


Acetabular Fractur Non concentric 1Acetabular Fracture Non Concentric 2


Any subluxation on CT demonstrates clinical instability

- fractures affecting 40% or more of the posterior wall are usually associated with instability

- fractures less than 40% should be screened for stability under II


4.  Other factors


Direct cartilage injury at time of impact

Neurological injury

AVN of head


Acute management





Neurovascular assessment

Investigations - exclude Pipkin, NOF

Emergent reduction / skeletal stabilisation

Assess stability

Re-evaluate sciatic nerve


Insertion Femoral Steinman Pin



- displaced acetabular fracture


Femoral Steinman Pin APFemoral Steinman Pin Lateral



- above blummenstaat's line

- in metaphyseal bone

- minimum 10 pounds weight, may need more

- assess post operative reduction


Acetabular Fracture Pre Steinman PinAcetabular Fracture Post Steinman Pin


Goals of Management


1.  Restore Articular Congruency

2.  Reduce & Maintain Hip in Acetabulum


Non operative Management


Radiographic factors


1.  Articular step < 2mm

2.  Weight bearing roof intact

- Matta Roof > 45o

- CT subchondral roof 10 mm

3.  Congruent reduction

4.  Stable < 40% posterior wall fracture




Tornetta JBJS Br 1999

- 38 hips with above criteria for 2.7 years

- good or excellent outcome in 91%

- poor outcome related to other injuries


Patient factors



Osteoporotic bone

Pre-existing arthritis


The elderly patient can have a THR as salvage if required down the track


Operative Management




1.  Incongruent reduction

2.  Non intact weight bearing dome

3.  Articular step > 2mm 

4.  Retained fragment

5.  > 40% posterior wall or instability


Surgical factors


1.  Surgeon experience

- steep learning curve


Letournel & Judet Fractures of the Acetabulum 1993

- initial rate non anatomical reduction 32%

- 4 years later 10%


2.  Surgical timing


Letournel & Judet

- anatomical reduction in only 50% operated after 21 days

- if operate too early, bleeding +++


3.  Fracture complexity


Matta  JBJS Am 1996

- 262 patients

- 96% elemental fractures anatomically reduced

- 64% complex






1.  Anatomic reduction

2.  Provisional fixation with lag screws 

3.  Buttressing with curved reconstruction plates 




1.  Posterior / Kocher-Langenbeck approach

- posterior column / wall


2.  Ilioinguinal approach

- anterior column / wall


3.  Extended iliofemoral approach

- Smith-Petersen extended over iliac crest

- for transverse / both column fractures


4.  Triradiate approach

- Kocher-Langenbeck with anterior extension from GT to ASIS

- wide exposure for both column fractures

- high incidence HO


Triradiate approach Both Column Fracture


Preferred option is to perform

- ilioinguinal for anterior column / wall

- posterior / Kocher Langenbeck for posterior column / wall

- do both 1 week apart for combined fractures




Posterior Column & Wall Fracture


Acetabulum Posterior Wall Plating 1Acetabulum Posterior Wall Plating 2Acetabulum Posterior Wall Plating 3



- IDC, radiolucent table, IV Abx

- lateral position but patient rolled excessively over

- patient 45o up from table, exposes posterior

- top leg hip flexed, knee flexed

- bottom leg extended

- blankets under top leg

- lateral support in front of top knee to prevent too much hip flexion

- prevents excessive tension on sciatic nerve


Standard posterior approach

- divide fascia lata

- find and protect sciatic nerve at all times

- do so by keeping hip extended and knee flexed

- expose short external rotators, divide 1cm from insertion to preserve blood supply

- usually must divide some of G. max

- elevate G medius from ilium

- steinmann pin in ilium for exposure

- expose ischial tuberosity by elevating biceps femoris, again protecting sciatic nerve at all time

- steinmann pin in ischium


Reduction can be aided but applying femoral distracter

- between ilial and ischial pins


Expose fracture

- posterior wall fracture, elevate and clean callous

- capsule usually partially avulsed

- ensure no femoral head fractures or loose fragments

- posterior column fracture often up in ilium, can put a plate across it



- often indirect

- buttress plate from Ischial Tuberosity to Ilium

- contour or use pre-contoured

- screws at plate extremities

- often 2 parallel plates if wall and column fracture


II to ensure screws not in acetabulum


Anterior Column & Wall Fracture


Acetabulum ORIF 2 Column APAcetabulum ORIF 2 Column Judet 1Acetabular ORIF 2 Column Judet 2



- radiolucent table

- IDC to decompress bladder

- IV Abx

- sandbag under operative side for some elevation

- need to prep and drape pelvis so can virtually access both ASIS 

- often need to get  across pubis


Ilioinguinal approach


Curvilinear incision from above pubis to ASIS

- identify and protect LFCN / below ASIS

- divide external oblique 1 cm above inguinal ligament

- identify and protect spermatic cord / round ligament

- divide posterior wall / internal oblique and transversus


3 windows (medial / middle / lateral)

- find external iliac artery and vein with peanuts / place sling

- find psoas and femoral nerve / place sling

- find iliopectineal fascia between vessels and psoas and divide with scissors


Medial window medial to vessels

- superior pubic rami

- may have to release some of rectus


Beware corona mortis

- anomolous vascular connection

- 10 - 15% patients

- between external iliac / epigastric artery

- to obturator artery


Middle window between psoas and vessels

- exposes quadrilateral plate


Lateral window lateral to psoas

- elevate iliacus off crest to expose fracture in iliac wing

- exposes around to SIJ




1.  Reduce quadrilateral plate

- small T plate / will sit under pelvic reconstruction plate

- separate recon plate


ORIF Quadrilateral Plate


2.  Plate iliac crest fracture

- long 13 hole plate from pubis

- along superior pubic ramus up onto inner table of ilium

- indirect acetabular reduction




Judet and Letournel 1980 417 Fractures

- 73% perfect reduction with 84% very good results

- imperfect reduction 55% good results

- infection 5.6% / heterotopic bone 18%

- poor results related to > 3 weeks


Matta 1996 258 Fractures

- anatomical reduction 71% with 76% excellent to good results

- poor results related to injuries to femoral head / age / post-operative complications

- AVN 3%




Heterotopic Ossification

- ilioinguinal 1%

- Kocher-Langenbeck 7%

- extended Iliofemoral 12%


Failure of fixation


Acetabular Fracture Failed ORIF 1Acetabular Fracture Failed ORIF 2


Very problematic

- often need revision to THR

- pelvic discontinuity must be addressed


Acetabular Fracture Failed ORIF CT 1Acetabular Fracture Failed ORIF CT 2THR Post Acetabular Fracture



- rate very high

- prevent with mechanical and chemical prophylaxis


Sciatic nerve injury 2% 

- especially with posterior approach


AVN 2%

- higher with posterior dislocations and Pipkin fractures



- occur in 2-5%

- increased in the presence of Morel-Lavallee lesion



- the most common complication

- anatomic reduction - 10%, usually after 10 years

- imperfect reduction - 45%, usually before 10 years 2,6


Hip OA post Acetabular FractureHip OA post Acetabular Fracture


Bladder and spermatic cord injury


Hernia formation


Vascular injury


External iliac vein

- control distally with vessiloop

- suture with 5.0 / 6.0 prolene on noncutting needle







IndicationsHip Fusion


Young adult 

- 16 - 30 years old

- monoarticular disease

- heavy demand 


Exhausted options of osteotomy

- risk of THA failure  / multiple revision surgeries considered too high


Aims of arthrodesis


Maximise bony contact

Minimise shortening

Provide rigid internal fixation

Compress the fusion site

Facilitate future conversion to THR





- difficulties in obtaining arthrodesis without femoral bone stock


Poor bone stock due other causes


Bilateral hip disease

- need ROM in other hip 90o

- in order to compensate in gait


Polyarticular disease eg Rheumatoid arthritis

- likely to develop hip / knee / back OA


Degenerative disc disease

- lumbar spine ROM important to compensate in gait and ability to sit in chair


Stiff ipsilateral knee or contralateral hip 




Good pain relief


No activity restriction

- most patients employed

- can return to normal jobs, even heavy labour

- most able to walk > 1 mile


Long term solution c.f. THA




Functionally inferior to THA


Increased stress on other joints


1.  Lumbar spine 

- 50% back pain

- most common reason for converting to THR


2.  Ipsilateral knee 

- 50% knee pain and instability

- increase rotation demanded in knee due to arthrodesis


3.  Contralateral hip

- has to compensate with increased ROM

- may predispose to OA

- will certainly worsen any underlying arthritis


Difficulties with certain activities



Supine sex


Sitting erect in chair

Difficulty putting on shoes


Gait abnormalities


Increased energy requirements

- increased oxygen consumption

- gait 50% less efficient


Increased lumbar lordosis to compensate 

- decreases stride length

- shortened stance phase

- contralateral hip has increased mobility compared to normal






To retain option of conversion to THR 

- don't use pelvic osteotomy

- preserve abductors




1.  Intra-articular

- most common

- allows disease to be addressed

- better correction of deformity

- difficult in paediatrics due to large amount of cartilage present


2.  Extra-articular


3.  Combined

- usually use combination 




Sagittal / 25° flexion

- <20° flexion - difficult to sit

- >25° flexion - difficult to walk due to LLD


Coronal / 5° adduction

- never abduction: can't walk, fall over even with 5° abduction

- too much adduction: LLD


Rotation / 15° ER 


< 2 cm LLD




Pseudarthrosis - 10% 



Methods to Increase Union


1.  Inter-trochanteric / subtrochanteric osteotomy 

- can increase union rate by decreasing lever arm of abductors

- come back 6/52 later and fix intertrochanteric fracture


2.  Vascularised bony extra-articular method

- iliac crest with Tensor Fascia Lata still attached

- the graft is inserted into trough in the anterior joint




1.  Lateral cobra plate

- detach GT

- pelvis to femur

- nil pelvis osteotomy


Hip Fusion Cobra Plate


2.  DHS

- Sunderland method


Hip Fusion APHip Fusion Lateral 2


3.  Anterior plating

- Smith Peterson approach


4.  Double plating

- anterior and lateral plate


Sunderland Method


Intra-articular approach /  2 hole DHS




Radiolucent table with II

- supine


Smith Peterson approach

- leave abductors intact

- dislocate hip anteriorly

- between sartorius and TFL

- between G medius and Rectus Femoris

- take off reflected head


Remove cartilage from head & acetabulum

- cup arthroplasty instruments useful

- approximate raw surfaces

- pack cancellous autograft

- position hip & hold with guide-wires temporarily

- place one guide wire central in head


Check position of hip

- need to be able to do intra-operative Thomas test

- FFD 25o / Add 5o / ER 15o


Fix with 150° DHS

- through joint into thick supra-acetabular area of ilium

- supplement with additional screws as necessary

- +/- Sub-Trochanteric Osteotomy


Spica at 2/52 for final position 

- NWB until xray union union


Schneider Technique 


Previously very popular technique

- don't use now as THR conversion not possible 


Characterised by pelvic osteotomy

- increases surface area for fusion

- pelvic osteotomy compromises future THR conversion


Femoral head compressed into osteotomised pelvis

- Lateral Cobra plate fixed to pelvis




Lack of head technique

- for post AVN or failed THR

- using a lateral Cobra plate & inserting the neck into the acetabulum


Lateral approach with GT osteotomy

- reflect abductors cephalad

- denude acetabular cartilage

- apply lateral cobra plate

- fix the GT to the arthrodesis with screws and place graft at the site

- +/- anterior plate


Britian Technique 


Extra-articular arthrodesis

- ischio-femoral arthrodesis

- oblique subtrochanteric osteotomy

- place tibial cortical graft from inferior femur to osteotomy in ischium

- medialize femur on graft

- spica


Results of Arthrodesis


Sponseller JBJS 1984 (classic report)


53 patients at 20 years post fusion

- average age 14 years

- back pain 60% / similar incidence back pain to general POP

- ipsilateral knee pain 40%

- contralateral hip 20%

- pain was unrelated to length of arthrodesis

- high functional abilities / played sport

- knee laxity of MCL was common 2° to hip excesssive adduction in fusion

- 15% conversion to THR (for back or knee pain)


TKR with fused Hip


Technically difficult

- have knee over edge of bed

- only way to get high flexion of knee for insertion tibial prosthesis


Poor results

- poor ROM


Best to revise arthrodesis first

- not if abductors not functioning


Conversion to THR



- back pain main indication

- ipsilateral knee pain

- contralateral hip pain 




1. Abductors 

- adequate function related to good outcome

- test by palpation preoperatively


2. Reason for fusion ?infection


3. Bony loss at acetabulum & femur


4. LLD

- average 2cm


5. Skin


6.  Higher failure than 1° THR




Good relief of LBP

- less so hip and knee

- most patients happy

- hip scores change little (owing to good results from arthrodesis)


LL equality achieved


Improved ROM


Gait poor for a couple of years

- related to abductor function

- intensive physio required



- 80% 10 year

- increased risk of infection





Removal of loose / foreign bodies


Hip Scope Loose BodyHip Scope Loose Body RetrievalHip Loose Body


Synovial biopsy / subtotal synovectomy / synovial chondromatosis

Management of labral tears / CAM Lesions

Osteochondritis dissecans / chondral lesions

Treatment of pyarthrosis





Lateral decubitus

II and traction


Hip Arthroscopy Set up





- both longitudinal & lateral in direction with vector parallel to femoral neck

- force required to distract femoral head varies considerably 

- range from 25 lb to 200 lb in unanesthetised adult volunteers

- majority performed with 50 lb (225 N) or less 

- important to limit periods of distraction with higher forces



1.  GA & skeletal muscle relaxation

2.  Negative intra-articular pressure

- released via joint capsule puncture with spinal needle + saline

- reduces force for distraction by 1/2

- "vacuum effect"





- viewing portal



- working portal



- working portal


Portal Placement


Hip Arthroscopy DistractionHip Arthroscopy InsufflationHip Arthroscopy Trochar InsertionHip Arthroscopy Cannular


Anterolateral portal / viewing portal


Anterolateral Portal 1Anterolateral Portal 2Anterolateral Portal 3


Insertion point

- 2 cm anterior to GT

- superior aspect of GT


Inserted under fluoroscopic guidance

- spinal needle directed medially & superiorly at 45° in each plane

- aim towards sourcil but under labrum

- joint distraction increases space in joint

- joint distended with normal saline

- guide wire inserted / blunt trochar / cannula



- LFCN - may result in partial or complete neuropraxia


Hip Arthroscopy Anterolateral InstrumentationHip Scope Air Arthrogram


Anterior portal / working portal


Anterior Portal 1Anterior Portal 2Hip Scope Nerves at Risk


Intersection of perpendicular lines

- superior aspect of GT and inferiorly from ASIS


Inserted under direct vision

- guide wire / trochar / cannula



- femoral NV bundle is 3 to 4 cm medial to insertion site 

- if placed inferior to neck ascending branch of lateral femoral circumflex artery is at risk


Hip Scope Anterior PortalHip Scope Anterior Portal 1Hip Scope Anterior Portal 2


Posterolateral Portal


Insertion point

- 2 cm posterior to GT

- level with superior border GT



- insert drainage portal

- improves visualisation



- sciatic nerve especially if foot ER during insertion


Posterior PortalHip Scope Nerves at Risk 2




Central compartment

- femoral head in acetabulum

- examine chondral surfaces

- examine labrum / debride / repair


Hip Arthroscopy Central Compartment



- head neck junction

- hip flexed, traction removed

- capsulotomy often required

- removal of CAM lesions


Hip Arthroscopy Peripheral Compartment






LFCN - anterolateral portal

Pudendal - traction

Sciatic - from traction / posterolateral portal


Pressure necrosis


Foot, scrotum, or perineum 




Scuffing of articular surfaces 







Femoral Head Fractures



5-15% of posterior dislocations




Posterior hip dislocation


Pipkin Classification


Type I - head fracture below fovea



- non operative



- excise fragment if small

- ORIF fragment if large (can contribute to instability)


Pipkin Fracture Type 1


Type II - head fracture above fovea



- rare, usually unstable



- excise if small

- ORIF if large


Type III - Type I/II with NOF fracture



- very high incidence of AVN



- ORIF young patient

- hemiarthroplasty / THR older patient


Pipkin Fracture Type 3


Type IV - Type I/II/III associated with acetabular fracture


Pipkin 4 Fracture


Non operative management




Type 1

- < 2mm displacement

- stable hip

- congruent joint


Type 2

- rarely anatomic

- usually unstable


Surgical Management


Choice of Approach


Fragment usually anteromedial


Type 1 and II

- anterior or anterolateral approach

- Smith Petersen / Watson Jones

- careful capsulotomy to preserve blood supply

- deep branch MCFA runs along superior femoral neck


Pipkin Open 1Pipkin Open 2Pipkin Open 3Pipkin ORIF


Type III

- anterolateral approach / Watson Jones

- ORIF NOF + fix/excise Pipkin fracture in young patient

- very high incidence AVN

- THR > 60


Type IV


A.  Associated with posterior dislocation / non operative acetabular fracture


Posterior approach

- this can make it difficult to access fragment

- need IR +++

- can attempt posterior to anterior screw fixation


Anterior approach

- if stable and no acetabular fracture requring ORIF

- involves making anterior capsulotomy

- patient already has posterior capsular defect


B.  Associated with posterior acetabular wall fracture that needs ORIF (>40%)

- posterior approach


C.  Associated with anterior acetabular fracture

- ilioinguinal with SP extension


Anterior Approaches


Many options

- Hardinge

- Watson Jones

- Smith Peterson 

- Ganz osteotomy


Any of these are blood supply preserving if perform safe capsulotomy

- avoid capsulotomy along superior neck

- Z capsulotomy

- capsulotomy along anterior acetabular rim superior to inferior

- along inferior femoral neck

- down medial femur


Ganz trochanteric flip osteotomy

- trochanteric slide

- gluteus medius and sastus lateralis attached / digastric

- osteotomy with saw posterior to anterior

- leave short external rotators attached to preserve deep branch MCFA

- slide GT fragment anteriorly

- capsulotomy as above

- allows access to anterior aspect femoral head

- dislocate femoral head anteriorly / surgical dislocation


Smith-Petersen approach

- good approach if only Pipkin fracture needs fixation

- higher risk of HO




Sciatic nerve injury 4%

- traumatic

- iatrogenic


Infection 3%


Recurrent instability

- large femoral head fracture excised

- posterior wall fracture

- rarely due to labral tear





- increased with anterior approach






Giannoudis et al Injury 2009

- systematic review

- Pipkin I: excision gave better results than fixation

- Pipkin II: ORIF
- AVN 11% / OA 20% / HO 17%

- no difference between trochanteric flip / anterior or posterior approach


Chen et al Int Orthop 2010

- RCT of excision v non operative for Pipkin 1 in fracture dislocation

- better outcomes in excision


Femoral Osteotomy





Prevention OA i.e SUFE / Perthes / DDH


Non union

Coxa Vara






Most OA is secondary to pre-existing disease 

- predisposes to articular cartilage failure

- failure of cartilage can be halted by decrease in load

- osteotomy corrects the underlying deformity


Pain relief achieved by


1.  Mechanical 

- decrease in unit load 


2.  Biological 

- decrease intra-osseous pressure




1.  Dysplasia 45%

2.  Perthes   20%

3.  SUFE 10%




< 25 - 30 years


Natural History


OA by age 50 in

- 50% with DDH / Perthes

- 20% with SUFE




1.  Correct deformity

2.  Increase congruency / decrease unit load

3.  Decrease JRF


Types of Osteotomy



- varus / valgus

- flexion / extension

- combination



- before OA begins

- age < 25 years

- Biological plasticity remains

- at-risk hip / painful hip ~ Ganz

- i.e. difficult to justify in the non painful hip



- before end stage OA occurs

- age < 50 years

- pathogenesis secondary to malalignment

- moderate OA where congruence increased by osteotomy




ROM important


1.  Flexion / extension arc

- >/= 90° to consider osteotomy


2.  Abduction / adduction arc 

- correction should not exceed arc


Flexion / adduction contractures common

- correct with valgus / extension osteotomy




AP pelvis


True lateral (Faux Profile) 

- lateral of pelvis with patient turned 25° to xray beam     

- to assess anterior uncovering

- VCA angle


Maximum Abduction / Adduction AP 


Von Rosen

- maximum abduction & IR








Examine nature of joint surface





Osteotomy Options





Flexion / Internal Rotation

Neck Lengthening


Varus Osteotomy / Pauwels Type I





- improve coverage

- rarely done alone

- only if little or no acetabular dysplasia

- CE > 15 - 20o



- improve coverage



- if medial head involved (unusual)


Coxa Valga > 135°

- lateral subluxation of head

- signs of lateral overload i.e. eccentric sourcil

- adduction contracture



- spherical head 

- increased congruity in max abduction

- minimum 15o abduction



- lateral head osteophyte



- subtrochanteric osteotomy

- medial shaft displacement 10 - 15 mm

- 120o Synthes locking plate with offset


Valgus Intertrochanteric / Pauwels Type II




1.  AVN

- to unload anterolateral head

- usually valgus flexion


2.  Subcapital fracture nonunion


3.  Severe medial OA with medial osteophytes

- capital drop osteophyte

- inferomedial femoral head osteophyte

- acts as fulcrum against acetabular osteophyte

- widens the superolateral joint surface


4.  Coxa vara

- congenital / developmental

- fibrous dysplasia


5.  Protrusio in young patient


6.  Fixed abduction contracture




90° flexion & 15° adduction




Calculate osteotomy

- mostly would be aiming for neck shaft angle 145 - 150o


Example coxa vara

- current neck shaft angle i.e. 110o

- desired neck shaft angle i.e. 145o

- require a 25correction



- use a 145o plate and screw

- place screw in centre of femoral neck and head

- thus when fixate the plate on femoral shaft, will have obtained desired correction



- mark proximal and distal femur with drill holes

- allows maintenance of current rotation / correction if required



- use 2 K wires

- usually performed at level of lesser trochanter

- insert distal wire parallel

- insert second wire at desired angle

- check with II / angle measurement devices

- may wish to insert distal steinman pin to control distal fragment

- anterior and posterior homan retractors

- osteotomy with saw


Close osteotomy

- apply plate

- use compression device Synthes


Extension Intertrochanteric Osteotomy




In association with correction in coronal plane

Anterior uncovering of femoral head in DDH

FFD / flexion contracture



- improved anterior covering of head

- eliminates FFD


Flexion / Internal Rotation Intertrochanteric Osteotomy




Severe SUFE 




Imhauser Technique




Femoroacetabular Impingement

DefinitionHip CAM CT 1


Aberrant morphology involving the proximal femur and acetabulum

- usually between the femoral neck and the acetabular rim

- during terminal motion of the hip


Can cause pain secondary to labral and chondral lesions

- may lead to early OA




Childhood conditions

- Perthes




Post trauma

- prior femoral neck fracture


Acetabular retroversion

- posteriorly orientated acetabular opening

- relative prominence of anterior rim

- crossing of anterior and posterior walls on the AP radiograph


Acetabular Crossover Sign


Previous periacetabular osteotomy



- profunda (deep socket)

- breva

- magna

- vara










Cam impingement 


Between head and acetabulum 


Abnormal femoral head morphology

- often with flexion

- damage to anterior labrum and shearing of cartilage (carpet lesions)


Usually young men


CAM lesion x-rayHip Cam LesionHip CT Anterior Cam Lesion


Pincer impingement 


Between neck and acetabulum


Hip Pincer Impingement


Due to overcoverage of femoral head

- profunda, protrusio

- acetabular retroversion / relative anterior rim overcoverage


Damage to anterior labrum




Young active males

- CAM impingement


Middle aged athletic women

- pincer impingement




Groin pain

- with rest

- with activity


Pain with flexion


Clicking from labral tear




Typically limited ROM


AP impingement 

- IR / flexion /  adduction

- most common


Posteroinferior impingement

- full extension and external rotation




True AP

- coccyx and symphysis pubis within 1-2cm of each other 

- for assesment of retroversion / crossover sign

- bony prominence junction anterolateral head and neck

- ossification of labrum

- acetabular spurs


Hip Cam Lesion Xray



- shows CAM


CT reconstruction


Very good for bony morphology


Case 1


CAM Lesion CT


Case 2


Hip Cam CT SagittalHip CT Cam 3DHip Cam CT 3D 2HIp Cam CT 3D 3




Labral lesions


Hip MRI Labral Tear CoronalHip CAM Anterior Labral Degenerative TearHip MRI Labral Lesion


Femoral head morphology / Alpha angle


T1 axial MRI

- circle drawn on circumference of femoral head

- line from centre to where head extends beyond circle

- line drawn to centre of femoral neck at its narrowest

- angle > 55o may be indicative of CAM


Hip MRI Anterior CAMHip CAM Alpha Angle


Beta angle


Distance between pathological head-neck junction and acetabular rim

- hip in 90o flexion




Non Operative


Activity modification


Usually problem does not resolve






Open femoral head arthoplasty with surgical dislocation

Hip arthroscopy


Open femoral head arthoplasty


A.  Surgical dislocation of femoral head


Ganz Osteotomy

- preservation of blood supply

- deep branch of medial circumflex artery most important

- runs posterior to obturator externus

- emerges at superior border of quadratus femoris

- over short external rotators

- then retinacular vessels up anterosuperior neck



- must preserve short external rotators

- trochanteric osteotomy

- greater trochanter slid anteriorly

- has abductors and vas lateralis attached

- capsule divided in lazy S

- preserving capsule over anterosuperior neck 

- reflected subperiosteally off neck (like banana skin)

- dividing lig teres and dislocating hip


B.  Femoral head osteoplasty

- allow flexion of 120o

- rotation of 40o


3.  Acetabular debridement 

- debridement acetabular chondral flaps

- osteotomy of the acetabular rim (up to 1cm)

- reattachment / debridement of labral lesions





- debridement of labral tears

- femoral head osteoplasty





- patient supine

- foot IR full initially, leg extended

- traction applied


Hip Arthroscopy Portal Insertion II


Anterolateral viewing portal

- hip distracted

- under II vision

- guide wire in place

- dilators, insert cannula


Anterior working portal

- triangulate, using II

- anterior labral and CAM resection


Hip Arthroscopy Anterior Portal


Posterior working portal

- accessory for labrum and rim


Assess Cartilage


Hip Arthroscopy Chondral DamageHip Arthroscopy Carpet Lesion


Assess for Labral Tears


Hip Arthroscopy Degenerative Labral Tear From CAM lesionHip scope normal acetabular Labrum


Labral resection

- with long resector


Hip Arthroscopy Initial ViewHip Arthroscopy Post Labral Resection


Acetabular rim resection

- if necessary

- long burr

- difficult to know extent of resection required

- check on II


CAM resection

- flex hip, ER

- T capsulotomy to expose CAM lesion

- performed with long thin scapel

- burr resection of CAM lesion

- again, under II guidance

- put hip through range to ensure adequate debridement

- T capsulotomy exposes CAM well

- isolated reports of hip dislocation


Hip Arthroscopy Labral and Rim ResectionHip Arthroscopy CAM Lesion ExposedHip Arthroscopy CAM resection


FAI Cam Resection 1FAI Cam Resection 2FAI Cam Resection 3






Larson et al Arthroscopy 2009

- retrospective comparison of labral debridement v fixation in CAM / Pincer

- significantly improved hip scores in repair grou

- 67% G/E in debridement

- 90% G/E in fixation


Athletes with CAM


Singh et al Arthroscopy 2010

- 27 Australian Rules Playes

- treatment of chondral lesions / labral lesions / majority with CAM lesions

- high level of satisfaction and 26/27 returned to high level sport




Byrd et al Arthroscopy 2009

- 10 year follow up

- 80% good results if no OA

- 7/8 with OA had THR at mean of 6 years



Hip Dislocation

IncidencePosterior Hip Dislocation


Young men


Posterior / Anterior 9:1




High velocity injury

- head direction at impact decides direction of dislocation


Anterior Dislocation 


Externally rotated & abducted leg

- flexion = inferior dislocation

- extension = pubic dislocation


Posterior Dislocation


Axial compression of adducted leg

- more flexion causes pure dislocation without fracture




Inherently stable joint

- large head on smaller neck

- allows deep seating of femoral head

- acetabulum deepened by labrum

- capsule reinforced by ilio/pubo/ischio femoral ligaments


40% femoral head in contact with articular cartilage

10% in contact with labrum


Blood supply


Majority by deep branch of Medial Circumflex Femoral Artery

- minimal by medial epiphyseal artery via ligamentum teres

- little to non via LCFA



- arises medial aspect of profunda

- along posterior intertrochanteric crest extracapsular / back of femoral neck

- passes between iliopsoas and pectineus medially

- runs along inferior border of obturator externus, above adductor brevis

- deep to quadratus femoris

- emerges between quadratus and inferior gemellus

- runs over conjoint tendon (2 gemelli and obturator internus)

- then penetrates capsule between conjoint and piriformis

- runs along superior aspect of neck to femoral head


Transverse branch (to ischium) and ascending branch (to trochanteric fossa0

- arise anterior to quadratus


Must protect this deep branch MCFA in a posterior approach


With dislocation and capsular tears

- some ascending cervical branches stretched/kinked

- emergent reduction can improve blood flow to femoral head


Associated Injuries


50-95% have other injury


Acetabular fracture


Femoral head fracture / Pipkin fracture


Sciatic nerve 10% / posterior dislocation


Patella fracture




Femoral artery injury - anterior dislocation


Femoral shaft fracture

- reduce head via steinman pin in proximal fragment

- then IMN femur






1. Medial / Central

- really medial displacement with acetabular fracture


2. Anterior 

- pubic / obturator / perineal


3. Posterior


Posterior Hip Dislocation Lateral




Capsule & Ligamentum teres torn


Labral tears & muscular injuries also occur


Y / iliofemoral ligament often intact with posterior dislocation

- blocks reduction

- bony fragments also block reduction


Clinical Features / Xray


Posterior dislocation

- leg shortened, flexed, adducted & internally rotated 

- head small on xray


Posterior Hip Dislocation


Anterior dislocation 

- leg short and externally rotated

- head larger on xray


Check NV status / sciatic nerve






Assess & manage life threatening injuries

- EMST / ATLS principles




1. Emergent reduction

- closed +/- open

- reduce risk AVN 



- < 6 hours 10%

- 20% - 50% if >24 hours


2.  Assess stability


Posterior wall fracture > 40%

- need ORIF for stability


Hip Dislocation Posterior Wall FractureHip Dislocation Posterior Wall Fracture


Posterior wall fracture < 40%

- can be unstable

- EUA after reduction to assess stability

- should be able to flex to 90o and some IR without instability


3. Screen for retained fragments


Compulsory CT

- xray will not detect fragments < 2mm


Hip Dislocation Loose Body


Remove / ORIF depending on size of fragment and location / Pipkin type


4. Reconstruct acetabulum if unstable or incongruent


Closed Reduction Posterior Dislocation




Full muscle paralysis on radiolucent table 

- supine

- assistant places downward pressure on ASIS

- operator up on bed grasping leg

- flex hip to 90o, flex knee to 90o



- ER head around acetabulum / axial traction or

- IR head around acetabulum / axial traction


Post reduction

- check concentric reduction on II

- check stability in flexion


Unstable reduction

- skeletal traction / femoral steinman pin


Post op


NV examination when patient awake

- ensure sciatic nerve working

- ensure hasn't become entrapped with reduction




Closed Reduction Anterior Dislocation



- as above

- traction in line with femur flexed

- internal rotation maneuver


Irreducible Dislocations



- 2-15%




1.  Capsule / Labrum / Ligamentum teres

2.  Muscle interposition

- anterior usually rectus / psoas

- posterior usually piriformis / G maximus

3. Bone fragment

4.  Muscle tone

- patient requires relaxant




Open reduction


Non-concentric Reduction


Esssential to obtain X-ray and CT after reduction



- head - teardrop distance must equal contralateral side



- only with CT can < 2mm fragments be seen


Pipkin Infrafoveal CT



- may be needed to see labral tears blocking reduction


Open reduction




1.  Irreducible dislocation


2.  Non-concentric reduction

- loose bodies / interposed tissue


3.  Post operative sciatic nerve palsy


4.  Unstable posterior acetabular fracture


5.  Associated NOF fracture


6.  ORIF Pipkin fracture




Usually from direction of dislocation

- preserve intact capsule

- preserve remaining blood supply

- i.e. with posterior dislocation the posterior capsule will be torn

- provides entry into joint


Posterior Approach


Aim to preserve intact anterior capsule and blood supply

- beware sciatic nerve

- divide piriformis and conjoint tendon away from insertion to preserve deep branch MCFA

- may need to extend posterior capsular rent

- allows direct visualisation of blocks to reduction

- blocks include G. max, piriformis, capsule, bony fragments

- may need to excise ligamentum teres

- explore acetabulum for loose bodies

- close capsule afterwards

- may need to excise L Teres


Other issues


Posterior acetabular fracture

- ORIF if > 40% or unstable


Pipkin fracture

- manage as per Femoral Head Fractures


Subcapital fracture

- Watson Jones / Smith Peterson approach

- supplementary lateral approach to insert fixation


Post Operative


NWB for 6/52


Bone scan re vascularity 



- °AVN = FWB

- AVN = consider bisphosphonates


Yue et al J Orthop Trauma 2001

- 5/54 low blood flow on early SPECT

- no correlation with AVN






Related to

- time to reduction <12/24

- velocity of injury

- open reduction vs closed (x4)

- direction (anterior < posterior)



- < 6/24 = 2-10%

- > 12/24 = 52%



- posterior 17%

- anterior 2%


Tends to be localised

- revascularisation occurs on reduction

- damage to lateral & medial epiphyseal artery

- metaphyseal blood supply remains

- occurs in first 18 months





- 15 - 20 %




- instability

- incongruous reduction

- cartilage damage at time of dislocation


Philippon et al Arthroscopy 2009

- hip arthroscopy post traumatic dislocation in 14 athletes

- all had chondral defects, 11 had loose fragments

- all patients had labral tears


Sciatic Nerve Palsy 


Posterior dislocation

- 8 - 19%

- more common after fracture / dislocation



- usually partial CPN

- usually resolves


Only explore if onset after MUA


Else observe


Instability < 1%


Myostitis Ossificans



- usually little functional problem

Hip Fractures

Intertrochanteric Fractures

DefinitionHip Intertrochanteric Fracture Type 3


Fracture which extends between the trochanters of the proximal femur

- lower limit is inferior border of lesser tuberosity




Extra capsular / well vascularized


The key to stability is the posteromedial cortex





- 90% > 65

- peak at 80 years


F:M 2:1


NHx 1st year

- 1/3 die

- 1/3 worse function

- 1/3 same function


Mechanism of injury


Low energy injuries in osteoporotic patient

- direct = blow to GT

- indirect = torque force secondary to fall





- shortened

- externally rotated

- groin pain with leg movement




Judicious use of medications

- avoid confusing / sedating


Poor vision

- adapt home environment

- avoid slippery rugs etc


Adapt bathrooms for safety / stability


Hip pads


Dx Occult Hip Fractures




Hip pain

Normal Xray




CT scan

- easily obtained in emergency departments


Bone Scan

- 100% sensitive at 72 hours



- sensitive within 24 hours

- more expensive and difficult to obtain




Lubovsky et al Injury 2005

- compared CT and MRI

- MRI more accurate

- 4/6 CT inaccurate


Evans Classification 


Two main types

- Type 1 Intertrochanteric

- Type 2 Reverse Oblique



- depends on medial cortical reduction



- collapse into varus or shaft medialises

- comminuted PM cortex

- reverse oblique

- subtrochanteric extension


Type 1 Intertrochanteric


1.  2 part undisplaced & stable


Hip Intertrochanteric Fracture Type 3


2.  2 part displaced, but stable on reduction


Hip Displaced Intertrochanteric Fracture


3.  3 part with posterolateral support (GT fracture)


4. 3 part without posteromedial support (LT fracture)


Hip Intertrochanteric fracture Type 4


5. 4 part without posterolateral or medial support (combination 3 and 4)


Four Part Inter trochanteric fracture


Type II Reverse Oblique Type



Inherently unstable

- 2° tendency of femoral shaft fragment to shift medially


Modified Boyd Classification


Type I   21%

- nondisplaced & stable 


Type II   36%

- stable, but displaced fractures

- stable construct with pin and plate


Type III   28%

- unstable with pin and plate

- large posteromedial comminution 


Type IV  15%

- intertrochanteric with subtrochanteric component


Isolated GT Fracture


Isolated Greater Trochanter Fracture




Non operative




Little place for non operative treatment


Immobilization = Severe morbidity

- bed sores

- chest infection

- non-union




Unit for surgery


Incomplete fractures


Alam et al JBJS Br 2005

- 5 partial intertrochanteric fractures treated non operatively, 3 operatively

- no refractures

- similar length of hosptial stay




Medical Workup


1.  Improve any reversible medical disease


Otherwise surgery in first 24 hours


Consider Cause of fall

- exclude medical cause

- TIA / UTI / MI / Arrythmia



- electrolyte imbalance / anaemia

- pneumonia / UTI

- arrythmias


2.  Patient on anticoagulation

- operate if on plavix

- on warfarin, wait or use FFP to reduce INR < 1.6




Zuckerman et al JBJS Am 1995

- delay > 2 days increases mortality within the first postoperative year




Obtain stable anatomical reduction and allow early mobilisation




Sliding Hip Screw and Plate

Intramedullary Hip Screw

Calcar Replacing Prosthesis


Post operative


Mobilise +++


DVT prophylaxis

- chemical and mechanical




Foster et al J Orthop Trauma 1990

- higher morbidity if albumin< 3 (70%) than > 3 (17%)


Prevent secondary fractures

- vitamin D + calcium to all patients

- bisphosphonates if tolerated


Sliding hip screw and Plate


Hip Pin and Plate APHip Pin and Plate Lateral




Plate is a lateral tension band whilst the sliding screw allows controlled fracture impaction



1.  No lateral buttress 

2.  Reverse oblique fracture

3.  Subtrochanteric extension




Set up

- traction table with anatomic reduction

- traction, adduction, IR

- other leg: hip and knee flexed with hip abducted to allow II

- lateral approach to femur


Guide wire

- centred in femoral head in 2 planes 

- tip-apex distance < 25 mm


Tip - apex distance

- from tip of screw to apex femoral head

- accumulative on AP and lateral

- strong predictor of cut out

- < 25 mm, virtually zero

- > 25 mm, increases cut out


Measure angle

- wire in centre of neck / centre of head

- usually 130o prosthesis

- often only 135o available / need to be lower in neck

- being in the centre of the head is most important


Ream to within 5 mm of end of wire

- tap

- insert screw / tip apex distance < 25 mm

- attach plate


Options for improving stability


A.  Valgus Osteotomy for unstable Fractures



- reduces shear force

- increases compression

- stronger construct



- 135° plate placed in at 120°

- valgises proximal fragment 

- medializes shaft

- +/- lateral wedge removed / Sarmiento Valgus Osteotomy


Cochrane Database Sytemic Review 2009

- no evidence for improved outcome

- higher blood loss


B.  Trochanteric stabilisation plate



- buttresses the GT and prevents lateral displacement


Madsen et al J Orthop Trauma 1998

- compared first generation Gamma nail / CHS and DSH/TSP in unstable fractures

- DHS/ TSP had lowest rate of varus malunion / lag screw cutout / excessive lag screw sliding with medialisation

- CHS still had lowest rate of reoperation


Intra-medullary Hip Screw


Hip Intertrochanteri Fracture IMNHip Intertrochanteric IMN Lateral


Mechanical Advantages

- load sharing rather than load bearing

- decreases lever arm

- supports medial cortex

- less distance for collapse


Theoretical Surgical Advantages

- smaller incision / mini invasive

- reduced blood loss

- shorter surgical times



- reverse oblique

- unstable fracture / loss of lateral buttress / loss posteromedial support

- intertrochanteric extension

- pathological fractures




First generation Gamma Nail (Stryker) had 5% distal femoral fracture rate


Reasons for distal fracture

- fit and fill caused increased distal stresses (higher fracture with 16 mm diameter nail)

- no anterior bow

- poor distal locking technique (missed holes caused fractures)

- 2 distal screws


Second Generation intra-medullary hip screws


IMHS / Gamma Nail

- trochanteric entry

- decreased distal diameter

- shorter length (180 mm v 200mm)

- only 4o valgus offset

- 125 - 130o angle

- one distal screw with jig


Hip Reverse Obliquity Fracture IMN




Second Generation IMN v Sliding hip screws

- several prospective randomised studies

- very similar rates of complications

- similar cut out, blood loss, time of operation

- slight risk femoral fracture IMN

- learning curve for IMN (25 cases)


Cochrance database review 2008

- no evidence of superiority of IMN over sliding hip screw

- increased complications with nail


3.  Calcar replacing prosthesis



- salvage of failure of fixation

- severe comminution

- RA



- high cost

- higher morbidity / mortality

- high risk of dislocation




1.  Screw Cut Out 6%


Hip Pin and Plate Screw Cut outIntertrochanteric NOF Screw Cut out



- poor screw position

- 150° screw

- high tip apex distance



- 95o DCS

- THR / calcar replacing prosthesis


THR Issues


A.  Cemented femoral component

- cement will come out screw holes

- Option 1:  leave screws in laterally, and strip medially to insert small screws

- Option 2:  use uncemented stem


B.  Length of femoral stem

- should bypass distal screw hole by 2 cortical diameters


C.  Calcar

- normal stem usually sufficient if LT healed back on


THR Post Pin and PlateIntertrochanteric NOF Calcar Replacing THR


Barrel Impingement / Excessive Lateral sliding / Shaft medialisation




1.  Long screw

2.  Collapse with insufficent lateral buttress

3.  Reverse obliquity fracture


Intertrochanteric Fracture Barrel Impingement




1.  Fracture united

- remove screw


2.  Fracture non union

- revise fixation in young patient



Lateral Slide Off Proximal Fragment


Femoral medialisation


Due to

- insufficient lateral cortex

- reverse obliquity fracture


Use 95° plate


Non Union


Uncommon / 1%

- exclude infection



- continued pain (case 1)

- hardware failure (case 2)


Case 1


NOF Intertrochanteric Non unionNOF Intertrochanteric Nonunion CT


Case 2


Hip Broken Intertan NailHip Broken Intertan Non Union salvage




A. Closing lateral wedge valgising osteotomy + graft

- success 90% / indicated in younger patients

B.  95 degree DCS Plate

C.  Revision IMN



Infection 2-5%


Intertrochanteric Infected NonunionIntertrochanteric Infected Nonunion Spacer





- posterior sag of femur in unstable fracture

- get malrotation if use excessive IR to "reduce" fracture on II


Periprosthetic fracture


Usually fracture at tip of plate

- remove distal screws and insert retrograde nail


Subcapital Fractures


DefinitionGarden 3 Displaced Subcapital


Fracture distal to articular surface & proximal to intertrochanteric region




On average 4 years younger than intertrochanteric fracture


One year mortality as high as 36%


Only 1/3 will return to pre-fracture living environment


Mechanism of Injury


Direct or Indirect


1.  Direct blow GT 


2.  Posterior cortex impingement on rim

- 2° to ER

- acts as a fulcrum


3.  Bending torque > threshold 

- major trauma in young


4.  Violent muscle contraction


5. Cyclical loading / Insufficiency fracture








Poor mobility / vision


Blood Supply


Medial and lateral circumflex femoral arteries

- extracapsular anastomosis at base of neck

- retinacular / ascending cervical branches

- intra-capsular branches


Majority via MCFA

- almost none to head via LCFA

- small amount via medial epiphyseal via ligamentum teres



- medial aspect of profunda

- along posterior intertrochanteric crest extracapsular

- between iliopsoas laterally and pectineus medially

- runs along inferior border of obturator externus, deep to quadratus femoris

- emerges at superior aspect quadratus femoris

- runs anterior to conjoint tendon then penetrates capsule

- runs along superior aspect of neck



- arises lateral aspect of profunda

- transverse branch runs under sartorius and rectus over vas lateralis to supply proximal femur


Garden's Classification


Type I 


Incomplete valgus impacted fracture


Subcapital NOF Garden 1 CTSubcapital NOF Garden 1 Xray


Type II 


Complete fracture, undisplaced


Type III 


Displaced with capsule intact 

- trabeculae don't line up with acetabulum


Subcapital NOF Garden 3


Type IV 



- trabeculae line up with acetabulum


Subcapital Fracture Garden 4


Eliasson Acta Orthop Scanda 1988

- best to divide into displaced / undisplaced

- based on work showing poor interobserver reliablity with Garden's


Pauwel's Classification


Relates vertical shear vector

- more vertical the fracture

- increased risk of non union


Type I:    < 30° from horizontal

Type II:   30 - 50° from horizontal

Type III:  > 50° from horizontal 


Subcapital Fracture Pauwels Type III


Problem 2° to parallax error






Undisplaced < 10%

Displaced 20 - 33% (variable, not complete)


Non union


Undisplaced 5%

Displaced up to 33%


This complication is more likely to need surgery


Clinical presentation




Short & ER leg




Medical Workup


1.  Improve any reversible medical disease


Otherwise surgery in first 24 hours


Consider Cause of fall

- exclude medical cause

- TIA / UTI / MI / Arrythmia



- electrolyte imbalance / anaemia

- pneumonia / UTI

- arrythmias


2.  Patient on anticoagulation

- operate if on plavix

- on warfarin, wait or use FFP to reduce INR < 1.6






Displaced v undisplaced

Age of patient


Undisplaced Subcapital


Cannulated screws

DHS + derotation screw


Displaced Subcapital Algorithm


1.  Expected life > Prothesis Survival



- anatomical reduction / closed or open

- compressive screws / DHS + derotation screw


2.  Expected life < Prothesis Survival


Hemiarthroplasty < 5 years survival

THR 5-15 years survival


Rogmark et al JBJS Am 2002

- multicenter RCT patients > 70 years with displaced fracture

- ORIF 43% failure

- hemiarthroplasty 6% failure


Displaced Arthroplasty



Patient > 70


Gjertsen et al JBJS Am 2010

- 4335 patients > 70 with displaced subcapital fractures

- minimum 1 year follow up

- 1 year mortality same in each group / 25%

- 22% reoperation in ORIF v 3% in hemiarthroplasty

- more pain / higher dissatisfaction / lower quality life in ORIF group





- unipolar monoblock

- unipolar modular

- bipolar




Burgers et al Int Orthopaedics 2012

- THR v hemiarthroplasty

- 8 trials involving nearly 1000 patients

- THR 4% revision v HA 7% revision

- THR 9% dislocation v HA 3%

- THR 94 WOMAC v 78 HA


Hopley BMJ 2010

- THR may lead to lower reoperation rates and better functional outcomes compared with HA in older patients

- heterogeneity across the available trials preclude definitive statements


Ingull Int Orthop 2013

- RCT of cemented unipolar v bipolar HA

- 4 year follow-up in 120 patients aged 80 or more

- better EQ-5D in bipolar

- no difference in revision rates / acetabular erosion / HHS


Li et al PLoS One 2013

- meta-analysis of cemented v uncemented HA in elderly

- cemented better hip function, less postoperative pain, fewer intra-operative complications but longer surgical time

- no difference in revision rate


Australian Joint Registry 2010 Revision Rates


1.  > 85 

- unipolar monoblock 3.4% 7 years

- unipolar modular 2.1% 5 years

- bipolar 2.9% 7 year


2.  75-84

- unipolar monoblock 8.5% 9 years

- unipolar modular 5.5% 7 years

- bipolar 3.5% 7 years


3.  < 75 

- unipolar monoblock 17.5% 7 year

- unipolar modular 13.4% 7 year

- bipolar 6% 7 year revision rate









- non modular - Austin Moore / Thompsons /

- modular







- minimises fracture risk

- reduced risk thigh pain

- slightly increased cardiac risk with cement


Australian Joint Registry

- revision rates lower for cemented than uncemented

- for all types of hemiarthroplasty for NOF fractures




Posterior approach

- increased short term morbidity

- may increase dislocation risk



- take off anterior 1/3 abductor tendons


Prosthesis Options


Austin Moore

- press fit non modular unipolar

- only 2 sizes of stem

- small patients can fracture femur

- larger patients the stem can be loose

- AJR: 7.8% 9 year revision rate


Hip Austin Moore



- cemented non modular prosthesis

- no offset options

- AJR: 5.1% 7 year revision rate


Thompsons Hemiarthroplasty


Modular Unipolar

- based on standard THR concepts

- trial and insert femoral component / cemented or uncemented

- can use standard or high offset

- opportunity to adjust neck length

- attach head


Modular Hemiarthroplasty




Hip Bipolar



- metal femoral head articulates with polyethylene socket

- reduces motion at acetabular / metal interface

- in theory reduces acetabular cartilage wear / degeneration / pain



- less dislocation compared with THR

- less acetabular wear / protrusio compared with unipolar

- less pain compared with unipolar

- more motion

- lower revision rates compared with unipolar (AJR)



- high cost (close to some THR)

- may need open reduction in dislocation if femoral head disassociates from socket

- loss of motion interface / becomes unipolar)







- similar to THR in long term


Hemiarthoplasty dislocatedBipolar Dislocation


GT Fracture


Hip Hemiarthroplasty GT Fracture




Hip Hemiarthroplasty LLD




Groin pain from acetabular cartilage erosion

- most common complication


Severe acetabular wear


Bipolar Acetabular Destruction 1Bipolar Acetabular Destruction 2


Bipolar Acetabular Destruction Revision 1Bipolar Acetabular Destruction Revision 2






Acetabular disease (RA, Paget's, OA)

Young, active, mobile patient




1.  Dislocation


Increased early dislocation rate

Long term dislocation rate similar to hemiarthroplasty


Keating et al Health Technol Assess 2005

- randomised study of bipolar v THR

- 2.7% dislocation rate v 4.3%


2. Revision / Survivorship


Good long term survival


Lee et al JBJS Am 1998

- 94% 10 year survival


3. Function


Parker et al Cochrane Database Review

- THA has better functional outcome


Bekerom et al JBJS Br 2010

- RCT of hemiarthroplasty v THR in over 70

- 252 patients 5 year follow up

- no difference in Harris Hip scores, revision rate

- increased early and late dislocation in THR

- did not recommend THR in over 70

Displaced ORIF



< 60 with good bone stock and preserved joint space




Union rates increased with anatomical reduction



- closed reduction

- open reduction / if closed reduction fails



- no varus

- < 15o valgus

- < 10o AP plane


Assessment of reduction


1.  Femoral neck shaft angle


2.  Garden alignment index

- angle of compression trabeculae to femoral shaft on AP should be 160o

- angle of compression trabeculae to femoral shaft on lateral should be 180o


3.  Lowell's alignment theory

- head neck junction should make a smooth S / reverse S on all views


4.  Restoration of Shentons line


Closed Reduction


Set up


Traction table / radiolucent table


Leadbetter Maneuver



- flexion / adduction / traction / IR 

- circumduction / abduction

- reduction Check in extension

- "Foot in Palm Test"

- if sufficiently reduced will sit without ER




Cannulated screws / DHS + derotation screw


Aminian JOT 2007

- biomechanical study of strength of fixation of vertical fractures

- locking plate > dynamic condylar screw > dynamic hip screw / 3 cannulated screws





- decrease intracapsular pressure

- in animal models increases blood flow



- open capsulotomy via Smith Peterson

- percutaneous needle drainage of hematoma


Open Reduction


Set up


Radiolucent table

- floppy lateral with sandbag under affected hip


Technique Watson Jones approach


Lateral incision

- divide fascia lata

- interval between G medius and TFL

- can take some of G medius off to aid exposure

- flexing hip 20-30o helps exposure

- take reflected head of rectus femoris off anterior capsule


"T" ant capsulotomy / Z shaped

- avoid dissecting superior aspect of femoral neck where major artery of MCFA runs

- vertical limb down anterior edge acetabulum / preserve labrum

- horizontal limb along inferior aspect of femoral neck


Steinman pin in femoral head

- allows manipulation and reduction

- may need second steinman pin in femur

- obtain anatomical reduction under direct vision


Separate lateral approach

- split ITB and vastus lateralis

- fixation of reduction


Check reduction on II

- ensure no varus on AP

- obtain lateral by adducting and IR hip / ensure good reduction on lateral


Ensure 2 guide wires centrally in femoral head

- 2 hole DHS + derotation screw (strongest)

- 3 or 4 cannulated screws


Open subcapital ORIF


Technique Smith Petersen


Smith Petersen Approach 1Smith Petersen Approach 2Smith Petersen Approach ORIF




Unstable fracture

- augment with a plate on inferior neck


Displaced Subcapital Inferior PlateDisplaced ORIF Lateral






Rogmark et al JBJS Am 2002

- multicenter RCT patients > 70 years with displaced fracture

- ORIF 43% failure

- hemiarthroplasty 6% failure




Jain et al JBJS Am 2002

- retrospective review of displaced fractures in 29 patients < 60

- significant reduction in AVN if fixed within 12 hours






Subcapital NOF AVN




Undisplaced <10%

Displaced  20-33% 


Risk factors



Injury velocity

Delay in Reduction

Non-anatomical Reduction




Whole head or small wedge 

- most common anterosuperiorlateral



- existing med and lateral epiphyseal blood vessels

- metaphyseal BV crossing fracture

- reduced by mal-reduction / non union


Only 30% with AVN will need re operation


Management Options


Older patient

- arthroplasty


Younger patient

- forage / vascularized fibula graft / non vascularised bone graft

- osteotomy








Risk Factors


Intial displacement

Non anatomical reduction


No compression across fracture

Vascularity - can unite if avascular


Failed Subcapital ORIFSubcapital ORIF Lateral


Subcapital Nonunion 1Subcapital Nonunion 2




Older patient

- arthroplasty


Young patient

- valgus osteotomy


Subcapital NOF Non UnionSubcapital NOF Nonunion CTTHR post Subcapital Nonunion


Valgus osteotomy



- patient must have at least 15o adduction



- aim to reduce the angle of the neck fracture to between 20 - 30o from horizontal

- this places it perpendicular to the forces acting across the hip

- measure angle of fracture from horizontal (usually 40 - 50o up to 70o)

- difference is angle of correction (20 - 30o)



- insert guide wire in centre of head / for screw

- place K wire superiorly in same plane as this wire at level of LT

- second K wire below at angle of required osteotomy

- resect bone piece

- apply appropriately angle device

- ensure straight line down femur in AP and lateral if need subsequent THR

Undisplaced Management



Garden 1 / 2





- ~ 15% displacement rate with non operative management

- increased risk of non union

- reduced hospital in patient stays




Cannulated screws

DHS + derotation screw


3 cannulated screws


Hip Cannulated Screws



- lateral on traction table

- adequate reduction / no varus

- small incision

- 1 x inferior screw, 2 x superior screws

- ensure inferior screw entry is above LT to prevent fracture

- ensure threads cross fracture site entirely to obtain compression

- need correct screw length so screw head can compress against cortex


DHS and derotation screw


Subcapital Fracture DHS Derotation Screw




Parker et al Acta Orthop Scand 1998 69

- meta-analysis of 25 randomised trials

- no superiority of pin and plate over 3 cannulated screws

- less blood loss with cannulated screws





Subtrochanteric Fractures



Fracture below lesser trochanter / proximal 5 cm femur


 Subtrochanteric Fracture Long SpiralSubtrochanteri Fracture




Young patients / high velocity injuries

Old patients / osteoporosis


Fixation techniques




A. 95o Dynamic Condylar Screw / DCS plate



- revision

- very short proximal fragment


Pai J Orthop Trauma 1996

- 16 cases without no bone graft

- union in 15/16


B. Locking plates


Burkes JOT 2012

- 18 pertrochanteric fractures treated with Synthes locking plate

- catastrophic failure in 7 (37%)

- poor Harris Hip Scores in remainder

- postulated that construct too stiff


Forward JOT 2012

- biomechanical comparison of subtrochanteric fixation

- IMN strongest

- 90 degree condylar and locking plate similar strengths




Cephalomedullary nails / screws into femoral head

- reconstruction nail

- IMHS / Gamma Nail / Intertan



- load sharing


Subtrochanteric Intertan NailSubtrochanteric Femur Fracture Gamma NailReconstruction NailReconstruction Nail Spiral Blade




Lee et al J Trauma 2007

- RCT of DCS v recon nail in 66 young patients with comminuted subtrochanteric fractures

- no significant difference in union rates


Rahme et al J Orthop Surg 2007

- RCT 58 patients

- revision rate 28% in plate group v 0% in IMN


Technique IMN




Varus position associated with non union


Shukla Injury 2007

- case series of subtrochanteric fractures treated with IMN

- all nonunion occured with varus > 10 degrees




Subtrochanteric FractureSubtrochanteric Lateral


Usual with short proximal fragments

- proximal fragment abducted, ER and flexed

- difficult to obtain trochanteric entry and straight shot down femur

- tendency for guide wire to go medial

- difficult to avoid fixing proximal fragment in varus


Reduce proximal fragment first

- avoid lateral entry on trochanter

- avoid varus

- allows accurate passing of guide wire


Reduction techniques



- ball tipped spikes / steinman pin to proximal fragment

- reduce varus



- percutaneous clamp / temporary reduction of fracture

- cerclage wiring - involve soft tissue stripping / may block femoral head screws


Cerclage wires

- can hold reduction


Afsari JBJS Am 2010

- cerclage reduction of displaced subtrochanteric fractures

- 43/44 fracture united

- good outcomes, if soft tissue dissection minimized


 Subtrochanteric Varus APSubtrochanteric Femur Varus Lateral




Varus Malunion



- trendelenberg gait


- increases risk non union



May need to open reduce fracture before nailing


Subtrochanteric Fracture Malreduced0001Subtrochanteric Fracture Malreduced0002


Non union


Subtrochanteric Fracture Nonunion




Non antomical reduction (varus / flexion / persistent displacement)

Excessive soft tissue stripping

Infection - must exclude with blood tests






Failure Hardware / Broken nail

- use guide wires with hook at tip

- catch distal end of nail and retrieve


Management Options


A. 95 degree condylar plate

- reduction of malunion / takedown non union

- bone graft


Subtrochanteric NonunionDCS 95 degree


B.  Exchange nailing

- need to be able to obtain reduction


Subtrochanteric non union Broken IntertanSubtrochanteric Nonunion Revision Nail


C.  THR / calcar replacing


Calcar Replacing Prosthesis


Screw Cutout


Recon Nail Cut outRecon Nail Cutout LateralRecon Nail Cutout Salvage

Outcome Measures

Please refer to excellent website for details of all scores



1.  Disease specific outcome measures


Surgeon assessment



Harris Hip Score


JBJS Am 1969


A.  Patient History (90 points)

- pain, walking distance, limp, support

- stairs, sitting, shoes, public transport


B.  Patient Examination (10 points)

- ROM values



- < 70 poor

- 70 - 80 fair

- 80 - 90 good

- 90 - 100 excellint


Mayo Hip scores


80 points clinical


20 points xray


2.  Patient specific outcome measures


Assesses broader range of issues

- patient assessment


Oxford Hip scores



- pain

- function



Entirely patient history




Medical outcomes short form 36




Western Ontario McMaster Osteoarthritis Index

Symptoms / Pain / Function




Pelvic Fractures



Pelvis Anatomy


Pelvis is a true ring

- any anterior fracture must have a posterior injury as well

- integrity of the posterior sacroiliac complex is key


Bony Anatomy


2 innominate bones + sacrum

Symphysis pubis < 5mm

SI joint 2-4 mm


Soft Tissue Anatomy


Suspension bridge like complex of post ligaments


1.  Posterior sacroiliac ligaments 

- are strongest in body

- maintain sacrum in position in pelvis


2.  Anterior sacroiliac ligaments

- flat and strong 

- resist ER and shearing forces

- they do not have the strength of posterior ligaments


3.  Iliolumbar ligaments 

- iliac crest to transverse process of L5


4.  Sacrospinous ligaments

- transversely from lateral edge of sacrum to ischial spine

- resist ER of pelvis


5.  Sacrotuberous ligaments 

- from sacroiliac complex posterior to sacrospinous ligament

- pass down to ischial tuberosity

- resist vertical shear


Sacrospinous and Sacrotuberous are complementary 

- running at 90o to each other 

- adapted to the major forces acting upon the pelvis


Injury Patterns






Vertical shear


Young and Burgess Classification


APC / Anterior Posterior Compression


APC 1 - 1-2 cm diastasis, minimal SIJ diastasis anteriorly


Pelvic Fracture APC 2


APC 2 - ST/SS + anterior SIJ disrupted


Pelvis APC 2Pelvic Fracture APC 2


APC 3 - complete SIJ disruption, nil vertical displacement


LC / Lateral Compression


LC1 - pubic rami + sacral compression same side


Pelvic Lateral Compression Fracture LC1


LC2 - pubic rami + iliac wing fracture


Pelvic Fracture LC2


LC3 - pubic rami + contralateral open book


Vertical Shear


Through SIJ or sometimes iliac wing / sacrum


Vertical Shear Sacral Fracture


CM / combined mechanism


Tile Classification


Type A: Stable (posterior arch intact)


A1: Avulsion injury
A2: Iliac-wing or anterior-arch fracture due to a direct blow
A3: Transverse sacrococcygeal fracture


Type B: Partially stable (incomplete disruption of posterior arch)


B1:  Open-book injury (external rotation)
B2:  Lateral-compression injury (internal rotation)
B2-1: Ipsilateral anterior and posterior injuries
B2-2: Contralateral (bucket-handle) injuries
B3:  Bilateral


Type C: Unstable (complete disruption of posterior arch)


C1: Unilateral
C1-1: Iliac fracture
C1-2: Sacroiliac fracture-dislocation
C1-3: Sacral fracture
C2: Bilateral, with one side type B, one side type C
C3: Bilateral


Open book injuries



- external rotation force

- no vertical displacement




Stage I - symphysis open < 2.5cm

Stage II - symphysis open > 2.5cm

Stage III - >2.5cm with peroneal wound


Is continuum with increasing external rotation force

- < 2.5cm posterior SIJ ligaments intact (like pregnancy)

- as progresses further the anterior SIJ ligaments rupture

- eventually posterior complex can be incompetent and have vertically unstable pelvis

- essentially have hemi-pelvectomy


Lateral compression



- IR force applied to ileum or more commonly to greater trochanter

- as pelvis is compressed risk of pelvic viscera injury especially bladder is great

- with increasing IR posterior structures may yield

- usually anterior sacroiliac crush is so stable that reduction is difficult



- ipsilateral

- superior and inferior rami fractured or

- superior ramus fracture with symphysis disrupted or

- locked symphysis



- bucket Handle

- contra-lateral ER / open book

- usually direct blow to pelvis

- fractured pelvis rotates like a bucket handle

- leads to LLD

- to reduce LLD need rotatory moment rather than traction






2 Types

- APC 1 & 2

- lateral compression injury




Instability in the vertical plane

- no integrity of posterior ligamentous complex

- disruption of sacrospinous / sacrotuberous and posterior SI ligaments


Radiographic signs of instability

- SIJ > 5mm in any plane

- posterior fracture displacement

- avulsion 5th lumbar transverse process

- avulsion ischial spine (SS ligament)

- avulsion lateral border sacrum (ST ligament)


Sacrospinous Ligament Avulsion




Inlet view

- 40o caudal

- shows AP displacement of sacrum c.f. pelvis

- anterior and posterior sacral borders

- enables insertion of SI screws


Pelvis Inlet viewPelvis Inlet


Outlet view

- 40o cephalad

- vertical displacement of sacrum relative to ilium

- to check reduction of vertical shear in OT

- enables insertion of SI screws


Pelvis Outlet ViewPelvis Outlet


CT scan


Better defines posterior injury



Management Acute

EMST / ATLS PrinciplesPelvic Fracture APC


Usually polytrauma

- 10% mortality



1. Volume replacement

2. Reduce pelvic ring

3. Stop exsanguination

- external stabilisation / surgery / embolisation


Associated Local Injuries


Arterial bleeders

- internal pudendal most common

- iliolumbar / SGA / IGA / lateral sacral / internal iliac


Retroperitoneal veins / bone bleeding

- 85% of bleeding


Compound injury

- urethra, vagina, rectum, peroneum

- need diverting colostomy prior to any anterior approach

- retrograde urethrogram for blood at meatus +/- retropubic catheter

- triple antibiotics (penicillin / gentamicin / metronidazole)


Pelvic Fracture Retrograde Urethrogram Normal


Neurological Damage

- L5/S1 most common

- L2 - S4 possible


Depends on location of sacral fracture and displacement

1.  Lateral to foramen - 6%

2.  Through foramen - 28%

3.  Medial to foramen - 57%


Sacral Fracture Transforaminal


Morel - Lavalle Lesion

- skin degloving

- high risk of contamination

- don't place incisions through this region

- needs debridement prior to definitive surgery


Intra-abdominal bleeding

- 32%


Management of bleeding / Liverpool Protocol / NSW Institute of Trauma



- external fracture stabilisation

- embolisation

- surgical control





- good for small arterial bleeders

- not haemodynamically compromised patient with massive bleeding

- unable to embolise large vessels and patient will die whilst attempting technique


Direct surgical control 

- rarely indicated and seldom successful

- main indications for open surgery are the open pelvic fracture and

- massive vessel injury leading to a patient in extremis from hypovolaemic shock


If patient is in extremis 

- i.e. BP < 60mmHg with no response to fluid management

- thoracic and abdominal bleeding ruled out

- blood loss is retroperitoneal

- need immediate laparotomy and cross clamping of aorta to buy time / allow haemostasis and vessel repair


Management with angiography services available


1.  Small allquots fluid (100-200 mls) to maintain SBP 80 -90 mm Hg +

stabilise pelvis with non invasive device


2.  Abdominal fast scan


A.  Negative

- immediate interventional angiography

- if becomes stable, ICU, manage pelvic fracture

- if unstable, repeat fast scan

- if positive, OT

- if negative, repeat angiogram


B.  Positive

- laparotomy

- external fixation

- remain unstable, immediate interventional angiogram


Mx without angiography services available


1.  Manage initially as above


2.  Abdominal fast scan


A.  Negative or unknown

- if SBP < 70 mm Hg

- OT for surgical control of bleeding and pelvic packing

- await retrieval for interventional angiography


B.  Positive

- OT for laparotomy and external fixation

- await retrieval for interventional angiography if continues unstable


Provisional Stabilisation


Pelvic binder

- simple, easy to use

- adequately reduces pelvic space


C clamp


Enables posterior control

- contra-indicated in iliac wing fracture

- in sacral comminution can over compress


Entry point of steinmann pins

- intersection of 2 lines

- line parallel with femur

- line back from ASIS



- too anterior, perforate ilium, organ damage

- too posterior, enter greater sciatic notch with nerve and vessel damage


External Fixation


Decreases pelvic volume

- indicated in open book and unstable pelvis

- rarely required for lateral compression fractures

- simple 4 or 6 pin frame in iliac crest

- pins at 45o to each other

- rarely definitive as has nursing issues






Dalal et al J Trauma 1989

- review of 345 patients with relation to mortality

- brain injury compounded by shock major cause in LC

- shock, sepsis and ARDS in APC due to major abdominal trauma


Open fractures


Dente et al Am J Surg 2005

- 44 open pelvic fractures

- mortality 45% at average day 17

- concurrent intra-abdominal injury 89% mortality

- vertical shear fractures universally fatal

- pelvic sepsis 60% mortality


Angiogram / Embolisation


Miller et al J Trauma 2003

- 28 patients hemodynamically unstable pelvic fractures

- classified as non responders if BP < 90 after 2 units blood

- 26 had angiography, 73% had an arterial bleeder embolised

- recommended angio as first line treatment in non responders


Pelvic Packing


Cothren et al J Trauma 2007

- 28 patients hemodynamically unstable from pelvic fractures

- had external fixation and pelvic packing

- no deaths from acute bleeding


Fast scan


Fuchholtz et al J Trauma 2004

- 31 patients with unstable pelvic fractures and free fluid on FAST

- all but 1 had intra-abdominal pathology requiring surgery

- FAST negative in 49 patients, 3 of whom went on to require laparotomy




Management Definitive

APC compression




Non Operative

- < 2.5 cm displacement

- indicates SS and ST intact

- nil posterior opening




1.  > 2.5 cm

- single anterior plate through Pfannelstiel incision


2.  Posterior SIJ disruption

- reduction and posterior stabilisation

- usually with SI screws

- if comminuted may need posterior plating

- anterior plate


Pelvic APC ORIF 1Pelvic APC ORIF 2Pelvis APC ORIF 3


Pfannenstiel approach / Plating Pubic Symphysis




Set up

- supine on radiolucent table

- IDC to decompress bladder


Incision 2cm above pubis

- through fat and fascia

- avoid detaching rectus

- usually part torn off already


Reduction techniques

- during the reduction care must be taken to avoid trapping bladder or urethra in the symphysis when closing the clamp


A.  Assistant may apply pressure over each iliac crest or an external fixator can be applied

B.  Large pointed reduction clamp can be placed onto each pubic tubercle or through holes drilled in the bone

C.  Expose the medial obturator foramen and application of pelvic reduction forceps thru the medial aspect of the foramen


Superiorly applied plate

- pelvic reconstruction plate


Pelvis Pubic Symphysis Plate 1Pelvis Pubic Symphysis Plate 2Pelvis Pubic Symphysis Plate 3


Iliosacral Screws




Posterior sacral comminution / foraminal fracture

- may be better with anterior / posterior plating



Radiolucent table with II

- 45o cephalad and caudal

- inlet and outlet view


Must reduce joint / fracture initially

- reduce vertically with traction on limb / outlet view

- reduce AP usually via compression / inlet view


Guide wire insertion


Anatomic safe zone

- between S1 foramen and sup ala on outlet view (outlet view)

- between neural canal and anterior body  (inlet view)


Pelvis Sacroiliac Screws InletPelvis Sacroiliac Outlet


Insert 6.5 mm cannulated screw with compression




S1 nerve root inferiorly

Vessels and ureter anteriorly

Cauda equina posteriorly

L5 nerve root superiorly


Post operative


Check screw position with CT

NWB 6/52




S1 nerve root injury

SI osteoarthritis


Failure of fixation




Routt et al J Orthop Trauma 1997

- 177 patients treated with percutaneous SI screws

- open reduction required if unable to obtain closed reduction < 1cm widening

- inadequate II due to obesity or abdominal contrast in 18 patients

- 5 misplaced screws due to surgeon error with 1 transient L5 neuropraxia

- fixation failure in 7 patients usually due to head injury / non compliance / delayed union

- non union in 2 patients


Sacro-iliac Plating


A.  Anterior


Pelvic Anterior Sacroiliac Plate 1Pelvis Anterior Sacroiliac Plate 2Pelvis Anterior Sacroiliac Plate 3



- combination with anterior approaches

- anterior plating of pubic symphysis

- anterior approach acetabulum required



- use lateral window of ilioinguinal or stoppa approach

- L5 nerve root at risk


B.  Posterior



- comminuted posterior sacral injury



- patient prone

- vertical incision 1 cm lateral to PSIS

- from crest to sciatic notch

- incise and reflect G maximus

- apply transverse plate

- soft tissue can be a problem


Lateral Compression Fracture


Indications for ORIF


LLD  2.5 cm


Significant internal rotation

- risk of impingement

- especially young female / interfere with birth passage


Lateral Compression ORIF




External rotation external fixation


Vertically Unstable Fractures






Femoral steiman pin + 20lb weight to reduce vertical displacement

External fixation to pelvis




Anterior plate


Posterior stabilisation

- posterior SI screws / anterior or posterior plate




Griffin et al J Orthop Trauma 2006

- retrospective review of 62 patients treated with SI screws

- 4 failures in patients with vertical sacral fractures

- recommended plate fixation in this group


Non Ring Pelvic Fractures

Psoas Avulsion


Psoas Avulsion


Ileum Fracture


Ileum Fracture


ASIS Avulsion




AIIS Avulsion


Rectus femoris


Ischial Tuberosity avulsion



- see article on hamstring avulsion





Proximal Hamstring Tear



Adolescent apophyseal avulsion

- treat non operatively

- unless displaced > 2 cm



- soft tissue avulsion




Usually associated with sporting activities

- skiing

- water skiing


Violent contraction

- knee extended

- hip flexing




Biceps / Semimembranosus / Semitendinosus all attach here





Unble to run


Chronic tears

- may have some neuralgia symptoms




Large haematoma / bruise

Palpable defect

Distal retraction of muscle into thigh with contraction


Proximal Hamstring Rupture Bruise




May see bony avulsion




Proximal Hamstring Avulsion MRI CoronalProximal Hamstring Avulsion MRI Axial




Non operative




Harris et al Int J Sports Med 2011

- systematic review

- better subjective outcome / return to sport / hamstring strength with repair c.f. non operative

- better outcomes with acute (< 4 weeks) than chronic repair




Surgical Technique


Patient prone

- knee flexed over sterile gowns



- longitudinal incision centred on ischial tuberosity

- starting at gluteal crease


Superficial dissection

- divide fascia in line with incision

- preserve posterior femoral cutaneous nerve

- identify and elevate inferior edge of gluteus maximus


Deep dissection

- identify and preserve sciatic nerve (lateral to hamstring)

- identify hamstring tendon

- repair with multiple large suture anchors

- ensure no kinking of sciatic nerve at end of case


Hamstring Repair Sciatic NerveHamstring Repair Sciatic Nerve 2


Proximal Hamstring Rupture Post Op


Post op

- splint with knee flexed

- prevent hip flexion

- crutches


Proximal Hamstring Brace




Residual weakness (60 - 90% other side)



Chronic > 4 weeks


More difficult

- careful dissection of sciatic nerve from adhesions

- release hamstring tendon


Augment options

- autologous ITB

- allograft




Sarimo et al Am J Sports Med 2008 36

- 41 patients

- 5 chronic requiring achilles allograft

- 96% would have it done again, 80% return to sport

- no difference in strength between acute and chronic


Cohen Am J Sports Med 2012

- 52 patients

- 40 acute, 12 chronic

- 98% satisfied

- minimal difference in outcome between acute and chronic


Murray KSSTA 2009

- achilles allograft recon of chronic (6 months) rupture

- good outcome

Snapping Hip



Most common

- fascia lata on greater trochanter

- iliopsoas on lesser trochanter


1.  Intra-articular structures

- labrum

- ligamentum Teres

- loose bodies

- synovial chondromatosis

- osteochondoma


2.  Extra-articular structures

- fascia lata on greater trochanter (common) 

- iliopsoas on lesser trochanter / iliopectineal eminence 

- long head biceps femoris over ischial tuberosity

- iliofemoral ligament over femoral head


Iliotibial Band over GT




Usually painless

Can often be produced voluntarily




Hip flexion and internal rotation causes readily palpable snapping sensation

- tight iliotibial band subluxates over the greater trochanter




Majority of patients no treatment required

- rest

- iliotibial band stretching exercises

- NSAIDS +/- local corticosteroid injections



- rare persistent cases 

- elliptical resection of the iliotibial band over the greater trochanter + greater trochanteric bursectomy 


Iliopsoas Tendon



- snapping sensation felt in the groin as the hip is extended from a flexed position

- palpated as the supine patient extends the hip from a position of flexion / abduction & external rotation




Non operative as above



- resistant cases

- psoas lengthening

- resection prominence of lesser trochanter

- psoas division (can be done arthroscopically)




Sportsman's Hernia



Groin pain in athletes

- secondary to tear in external oblique fascia




Sports with aggressive adduction

- hockey / soccer




Tears in external oblique fascia

- tend to be central

- around spermatic cord and ilioinguinal nerve

- pain may be from nerve entrapment




Adductor Longus Tear

Osteitis Pubis


Symphysis Pubitis


Hip pathology




Adductor longus tears

- get better with time

- rarely need surgery

- pain stays below goin


Sports Hernia

- may have nerve / ilioinguinal symptoms

- above groin

- often get worse




Adductor longus tears

- tender over tendon

- pain / weakness on resisted adduction


Sports hernia

- tender over inguinal ring

- may have palpable dilatation of external inguinal ring

- pain with resisted sit up

- pain with resisted leg flexion


Dynamic ultrasound


May be useful in very experienced hands




Can be difficult to see

Is often a clinical diagnosis




Non Operative



Exclude other diagnosis




Hernia repair



- expose external oblique fascia

- identify and protect spermatic cord

- identify tears / pathology

- release ilioinguinal nerve

- repair primarily or with gortex mesh


Ilioinguinal nerve

- some surgeons cut the nerve

- risk neuroma

- suprapubic numbness only


Can combine with adductor tenotomy






THR Australian Joint Registry


2009 / Revision Rates 8 year


Prosthesis Type All Diagnosis 7 year


Unipolar Monoblock 6.8%

Unipolar Modular 6.8%

Bipolar Hemi 4.2%


Cemented THR 3.8%

Cementless THR 4.4%

Hybrid THR 3.9%


Total Resurfacing 5.4%

Thrust Plate 3.0%


Revision for OA 8 year


Conventional THR  4.0%

Total Resurfacing   5.3%


Partial Hip Replacement

Cemented better than cementless in all categories




1.  > 85 

- unipolar monoblock 3.4% 7 years

- unipolar modular 2.1% 5 years

- bipolar 2.9% 7 year


2.  75-84

- unipolar monoblock 8.5% 9 years

- unipolar modular 5.5% 7 years

- bipolar 3.5% 7 years


3.  < 75 

- unipolar monoblock 17.5% 7 year

- unipolar modular 13.4% 7 year

- bipolar 6% 7 year revision rate


Primary Conventional THR


By Age


< 55   4.9%

55-64  4.6%

65-74  3.6%

>75     3.7%


By Gender


Female  3.8%

Male     4.3%


By Fixation


Cemented    3.9%

Cementless  4.4%

Hybrid         3.4%


By Age & Fixation


< 55      hybrid (4.6) < cementless (4.8)

55-64     hybrid (3.6) < cementless (4.7)  < cemented (6.1)

65-74     hybrid (3.2) < cemented (3.8) < cementless (3.9)

> 75      cemented (3.1) < Hybrid (3.3) < cementless (4.2)


By Diagnosis


AVN 5.1%

DDH 3.5%

NOF  5.2%

OA    4.0%

RA    5.4%


By Bearing Surface


Ceramic / Ceramic  3.9%

Metal / Poly             3.2%

Ceramic / Poly         4.1%

Metal / Metal           7.7% (Head sizes > 28mm)


By Head Size


Ceramic / Ceramic

</= 28          4.6%

> 28              3.5%


Metal / Poly

>/= 28          3.9%

> 28              3.0%


By Cemented THR


MS30/Low Profile cup     1.0%

Exeter/Exeter                3.2%

Exeter / Contemporary   6.6%

Spectron / Reflection      6.9%


By Cementless THR


Securefit Plus / Trident  2.8%

Mallory Head                5.5%

Synergy/Reflection        3.8%

ABGII/ABGII                 5.6%


By Hybrid THR


Definition / Vitalock        1.5

Exeter/Vitalock              3.6%

Spectron/Reflection        5.4%


Identified as higher than expected


Corail / ASR 


Hip Resurfacing


13 300 procedures


Best outcome

- male < 65 with OA

- able to get > 50 mm head size

- 3.9% 9 year


Revision rate


Cumulative revision rate

- 7.2% 9 years for OA


Birmingham Resurfacing

- 6.2% 9 year


Reasons for revision

- fracture 36%

- loosening 33%

- metal sensitivity 7%


Revision by diagnosis 7 years

- OA 5.8%

- DDH 14%

- AVN 6%


Revision by prosthesis

- BHR 96.5% 5 year


Revision by age 7 years

- < 55     5.6%

- 55 - 64  5.8%

- > 65     7.3%


Revision by sex 7 years

- male 4.5%

- female 9.3%


Revision by head size 7 years

- < 44mm:    13.8%

- 45 - 49mm: 8.8%

- 50 - 54mm: 3.7%

- > 55mm:     2.2%






Femoral only 21.5%

Acetabular only 37.1%

Combined         35.8%




Loosening 45.7%

Dislocation           14.8%

Lysis                    10.1%

Fracture                9.2%

Infection               9.1%

Wear Acetabulum   3.3%

Pain                      2.1%


Re-revision Rate


Minor (head, liner)   19.4% 5 year

Major Partial            14.1% 5 year

Major Total               8.2%   3 year

THR Complications

DVT Prevention


ANZ Working Party on the Management and Prevention of Venous Thromboembolism 2007




Top 6 conditions associated with DVT

- stroke


- multi trauma


- hip fracture

- spinal cord injury


Not one of the 12 doctors was an orthopaedic surgeon




Heparin / LMWH / fondaparinux

- confirmed effectiveness



- not recommended

- at best weak effect in some people



- a role in some high risk surgical patient

- requires monitoring




Inconclusive in many areas


Recommend 28 - 35 days in

- hip fracture



Epidural Catheter


No anticoagulant within 12 hours of inserting / 6 hours of withdrawing epidural catheter


Mechanical compression


Graduated compression / intermittent pneumatic compression / foot pumps have all been shown to work


Recommended to combine with chemoprophylaxis


Use unless contra-indicated

- severe peripheral arterial disease or neuropathy


Specific Recommendations


THR / Hip Fracture


Enoxaparin 40 mg / day commencing 6 - 8 hours post op for 28 - 35 days 


TKR / Multi-trauma / Prior VTE / Cancer


Enoxaparin 40 mg / day commencing 6 - 8 hours post op

Post op for 5 - 10 days


Major Surgery (any surgery > 45 minutes)


Enoxaparin 20 mg / day commencing 6 - 8 hours post op for 5 - 10 days


High risk patients


Oestrogen therapy



Strong FHx VTE


Contraindications to chemoprophylaxis


Active bleeding

High risk bleeding

- hemophilia

- platelets < 50

- history GI bleeding

Severe hepatic disease (INR < 1.3)

Allergic to heparin

High risk of falls

Palliative Management





IncidenceTHR Dislocation


2-3% of cases 

- doubles with infrequent operator

- second most common reason for revision after loosening


Australian Joint Registry

- dislocation accounts for 14.8% of revisions




Posterior dislocation

- hip flexed, adducted, IR

- 80%

- usually getting out of chair


Anterior dislocation

- hip extended, adducted, ER


THR Anterior Dislocation




Early < 6/ 52

- majority of single dislocations

- usually excessive hip position by patient

- before adequate muscle control & soft tissue healing

- after six weeks strong pseudocapsule forms about hip

- adds to stability +++


Chance of recurrence 40%


Late > 6 weeks

- represents majority of recurrent dislocations

- sually due to increase in ROM & activity

- manifests unrecognised impingement / malposition


Chance of recurrence 60%




Surgeon factors

- experience

- approach

- component position

- component design

- soft tissue balance

- impingment


Patient factors

- soft tissue

- cognitive disorders

- NM disorders

- NOF fracture

- revision


Surgeon Factors


1.  Surgeon Experience

- < 30 THR per year

- 2 x dislocation rate


2.  Approach


A.  Increased with posterior approach

- common in early papers

- reduced with short ER repair / use of large heads / component position

- now equivalent rates to anterolateral


B.  Transtrochanteric

- increased with trochanteric non union x6


3.  Component position


Dislocated THR Open Acetabulum


A.  Acetabular safe zones

- abduction 40 +/- 10o

- anteversion 15 - 30o


B.  Excessive femoral anteversion

- especially when combined with excessive acetabular anteversion

- predisposes to anterior dislocation


C.  Ranawat concept of combined anteversion

- acetabular + femoral anterversion

- 25 - 35o for men

- 35 - 45o for women


D.  May wish to increase anteversion in posterior approach and reduce it in the anterior approach


4.  Component design


A.  Increased head size


THR Big Head Dislocation


Increased size increases head-neck ratio

- reduces impingement / increases arc of motion


Increased jump distance

- seated deeper in acetabulum

- decreases jump distance

- greater translation before dislocation


B.  Liner profile

- posteriorly elevated profiles

- i.e. neutral liners v 10o elevated rim liners

- theoretically more stable

- reduces dislocation rates early, but not late

- can cause impingement in extension and ER

- this may lead to dislocation and increased wear

- can put hood in variety of positions

- usually postero-superior


5.  Soft tissue tension


A.  Restore LLD and offset

- reduced offset associated with increased dislocation

- reduces ST tension

- increases risk of impingement


B.  Dislocations reduced with careful capsular and soft tissue repair

- reduces dislocation rate in posterior approach


6.  Impingement

- when two non articular surfaces come into contact during joint ROM

- decrease by increasing head neck ratio

- may be liner / osteophyte / excessive capsule

- always put hip through ROM

- ensure in full extension and ER, no posterior impingment

- ensure in flexion 90o and IR, no anterior impingment


Patient Factors


1.  Soft tissue function

- previous hip surgery 

- revision THR

- weak abductors


2.  Cognitive disorders

- dementia / delerium

- alcoholism


3.  NM disorders


4.  Women


5.  Post THR for Neck of Femur fracture

- no stabilising capsular hypertrophy / fibrosis seen in OA


6.  Revision

- dislocation rates higher in revision setting




Pre-operative education

- avoid dislocation in first 6 weeks



- restore offset and leg length




Posterior approach

- careful short ER repair


Trochanteric osteotomy

- large flat surface

- strong repair

- protected WB /52


Component positioning


A. Extrapelvic Landmarks

- careful patient positioning

- patient stable

- ASIS perpendicular to floor

- use guides on acetabular insertion jigs


B.  Intrapelvic Landmarks

- transverse acetabular ligament

- anterior and posterior acetabular walls if no osteophytes


Component design

- liner lip posterosuperior


Prevent impingement

- remove wall osteophytes

- restore offset

- anterior capsule can cause impingement

- avoid excess cement


Large head neck ratio


Trial reduction

- flex to 90o, IR 45o, adduct 20o

- full extension, ER 45o

- ensure stability

- restore offset

- check LLD


Post operative

- avoid extremes of position

- abduction pillow

- knee immobiliser in confused patients / limits hip flexion

- post-op education

- no driving, high chairs, low cars 6 weeks

- no crossing legs ever





- MUA 

- re-educated

- mobilise as tolerated




1st episode 

- treat with reduction



- treat with abduction brace 

- 20° flexion / Abudction / ER

- for 6/52



- revision


X-ray evaluation


A.  Component malposition


1.  Acetabular Abduction


Easy to assess on AP


THR Acetabulum Closed < 45 degreesTHR Acetabulum open > 45 degreesTHR Dislocation Abducted Acetabular Component


2.  Acetabular Anteversion


Much more difficult to assess

- compare ellipse of acetabulum on AP pelvis and AP hip



- AP pelvis the beam is centred over the pelvis

- AP hip the beam is centred over the hip


If cup anteverted

- looks flat on AP pelvis

- looks elliptical on AP hip


If cup retroverted

- looks elliptical on AP pelvis

- looks flat on AP hip


THR AP Pelvis Elliptical CUpTHR AP Hip Straight Cup


B.  Other


Eccentric liner wear

- draw lines on paper, compare each side

- thickness not equal both sides with wear


THR Poly Wear




Insufficient offset


Surgical Revision


Need to decide cause of problem

- preoperative and intraoperative

- malposition / impingement / soft tissue

- have options available to address each problem




1.  Impingement 

- removal of osteophytes or cement

- exchange components to improve head neck ratio

- may need to adjust component malposition


2.  Malposition 

- assess stem + cup on CT



- change for Augmented polyethylene lining (if uncemented cup)

- revise component positioning

- larger head technology


3.  Incorrect tissue tension 

- longer neck / correct offset


4.  Worn liner

- exchange liner


5. Abductor insufficiency 

- trochanteric advancement

- increase femoral offset (modular head, lateralised liner)




1.  Constrained cups


THR Constrained CUp



- an acetabular component that uses a mechanism to restrain the femoral head within the cup

- can be implanted denovo or cemented into well fixed cup

- usually has a metal locking ring



- deficient soft tissues

- paralysed abductors

- GT non union



A.  Cup and monopolar liner with locking ring

B.  Bipolar constrained liner with locking ring




A. A constrained cup may still dislocate

- usually require surgery to relocate / require revision


THR Dislocation Constrained Liner 1THR Dislocation Constrained Liner 2


B. Inhibit ROM and transmit significant forces, which may contribute to early loosening


2.  Failure or Unreliable patients 



- bipolar hemiarthroplasty

- girdlestones



Heterotopic Ossification

DefinitionHO Brooker 4


Extraskeletal bone formation in periarticular tissues 

- HA crystals within osteoid matrix


Different to calcification 

- osteoid matrix laid down




1.  Myositis Ossificans

- post traumatic


2.  Heterotopic Ossification / associated with TJR


3.  Neoplastic Ossification




Occurs 50-70% THR's

- significant in 20%

- clinically significant in 1%


More common in men x 2


Risk factors



- previous hip / other hip HO

- incidence is 80%



- hypertrophic OA

- active Ankylosing Spondylitis

- hyperostosis


- active Paget's 

- fracture (acetabular trauma, pre or intra operative)




- posterior approach < Hardinge < transtrochanteric




Similar cascade to fracture healing

- unknown trigger

- undifferentiated mesenchymal cells differentiate in osteoblasts

- occurs within first few days

- produce osteoid

- mineralised to bone (mature lamellar bone)


Two Precursor cells about the Hip / Friedenstein


1.  Determined Osteogenic Progenitor Cells

- from bone marrow

- develop into osteoblasts with inflammation


2.  Inducible Osteogenic Progenitor Cells

- need BMP to develop into osteoblasts


Brooker Classification


Only Type IV interferes with function


Type I:  Isolated islands of bone


Heterotropic Bone Brooker 1


Type II:  Bony spurs from pelves and proximal femur, gap > 1 cm


Heterotropic Bone Brooker 2


Type III:  Gap < 1 cm


Heterotropic Bone Brooker 3


Type IV:  Apparent ankylosis


Heterotropic Bone Brooker 4


Clinical Features


Usually none

- pain usually as it matures

- decreased ROM

- dislocation 2° impingement (rare due to loss of ROM)

- nerve irritation

- trochanteric bursitis

- hip can appear red, swollen and tender




New bone in peri prosthetic soft tissues

- visible by 3-6/52

- extent determined by 3/12


Maturation continues for 12-18/12 


Bone Scan


Increased uptake = continued activity

- remain increased for 12/12




Rise in serum alkaline phosphatase post surgery

- associated with HO




1.  Prevention 


Identify at patients risk preoperatively

- Ankylosing Spondylitis / Pagets / Previous HO / DISH


A.  Surgical Technique


Gentle handling of tissues

- avoid muscle stripping

- lavage tissues

- drain wound




Indomethacin 50 mg bd for 1 week

- significant reduction in risk of HO

- 7 days as effective as 14 days

- as effective as postoperative radiation


Risk of GIT side-effects ~ 20%

- interaction with anticoagulants

- double risk of significant bleeding with DVT prophylaxis




Knelles JBJS 1997

- 685 Primary THR

- 50mg bd Indocid for 1 week

- as effective as 1 x 7 Gy Post-op




For very high risk patients

- previous HO / indocid contraindicated because of PUD

- post surgical excision of HO



- 700 Rad / 7 Gy < day 5

- 800 Rad 6h pre-op prevents HO


Side effects

1.  Delay incorporation of bone graft / union of trochanter

2.  May delay porous ingrowth with uncemented components

3.  Can make patient nauseous

4.  Nil evidence wound problems (shielded, low dose)

5.  Risk of malignancy - nil evidence at this low dose


D. Biphosphonates


Delay calcification and delay Xray appearance of bone 

- doesn't prevent osteoid formation

- calcification occurs once drug stopped

- no longer used


2.  Surgical Excision




Significant symptoms / reduced ROM & > Brooker III

- revision of prosthesis




Usually 12-18 / 12 post-operatively

- mature appearance on XR

- cold Bone Scan

- serum ALP normal




Radiotherapy post oeratively as high risk 




Usually increased ROM

- unreliable effect on pain

- bone often reforms




THR HO Brooker 4THR HO Brooker 4 Poster ExcisionTHR Post HO Excision Dislocation









Infected THR

Risk factors




Advanced age

Immunosuppression - steroids / Rheumatoid / DM

Malnutrition - Lymphocyte count / Transferrin / Albumin

Vascular disease


Poor skin i.e. psoriasis

Previous infection in joint

Infection elsewhere - i.e. UTi

Prolonged hospital admission

Revision surgery


Operative Factors



- preoperative wash

- preoperative shave

- admission day of surgery to clean ward

- groin, nasal, axilla swabs clear

- clear urine (MCS preop)

- no skin breaks


Operative Period

- laminar flow

- minimal theatre traffic

- IV Abx on induction

- shields

- alcoholic prep

- prep drapes

- short procedure duration

- care of soft tissues

- ABx cement

- wound closure / drains / hemostasis


Postoperative Period

- wound haematoma & drainage

- skin necrosis

- post operative ABx

- management remote infections i.e. UTI

- care with dental procedures




Current rate 0.27 - 2 % 


Increased risk with high-risk patients (2%)

- immuno-compromised

- recurrent bacteraemia

- revision > 2%

- RA




S. epidermis most common with S. aureus second

- together make up two thirds of all infections


MRSA increasing in prevalence

Also vancomycin resistant S. aureus



- streptococcus

- S. capitus

- pseudomonas

- coliforms

- anaerobes

- mixed 1/4




Usually worsening hip pain

- often minimal constitutional symptoms




Progressive / rapid lysis / bone loss

May be normal appearing xray


Infected THR progressive bone loss and lysis




For full details, please see Investigation of Pain in THR Complications section




Fluid collection about hip




CRP > 10 and ESR > 30 very suspicious


Bone scan


Reveal increased uptake about both components

- blood flow, blood pool and delayed uptake phases

- more than 12/12 post implantation


Specificity increased by WC scan




Under II control

- off antibiotics

- confirm infection


THR Aspiration




1.  Prosthesis in bone

- difficult for antibiotics to access

- poor blood supply

- similar to osteomyelitis


2.  Glycocalyx 


Bacteria have two forms

A.  Planktonic form 

- individual free floating cells

B.  Sessile form 

- exist within biofilm of glycocalyx

- 500x more resistant than planktonic form


Glycocalyx is a slime layer of polysaccharides produced by bacteria 

- protective barrier against antimicrobial and host defences

- helps bacteria to exist and survive on synthetic substances

- biofilm requires minimum time to form

- infection can be irradicated by Abx while still in planktonic phase but not once form biofilm


3.  Prosthesis Surface Properties


CO-Cr more susceptible to infection than titanium

- may be related to faster osseointegration by titanium


Polished surfaces less susceptible

- smaller surface area for bacteria to adhere

- shorter distance for host cell to travel


Classification Gustilo 1993


1.  Early post-operative

- < 1/12

- febrile patient

- red swollen discharging wound


2.  Late post-operative

- indolent (low virulent)

- > 1/12



- well patient

- healed wound

- worsening of pain

- never pain-free interval


3.  Acute haematogenous

- antecedent bacteraemia

- can occur several years after surgery



- well patient

- previously well functioning hip

- UTi or other source of infection

- hip now very painful


4. Positive intra-operative culture

- presumptive diagnosis aseptic loosening

- intra-operative m/c/s comes back positive (2 out of 5)

- treat with 6 weeks Abx -> success rate 90% 






Eradicate infection

Relieve pain

Restore function




1.  ABx suppression

2.  Debridement and prosthesis retention

3.  One stage revision

4.  Two stage revision

5.  Three stage revision

6.  Resection arthroplasty


1. Antibiotic Suppression




1.  Gustillo Type 4 

- 90% success


2.  Elderly and frail




Known sensitive organism

Stable prosthesis

Tolerable oral Abx





- 50% retention of prosthesis at 3 years 


2. Debridement with Retention THR





- symptoms < 4/52



- well fixed prosthesis



- known sensitive organism



- Cierny A / B / C




No Abx until

- swab and tissue for M/C/S

- or after positive blood culture




Excision of all necrotic and infected tissue

- ensure implant well fixed

- exchange liner (if uncemented)

- wash +++

- monofilament nylon sutures

- drain


IV Abx 6/52


Vanco / genta initially until swabs available

- ID consult




1.  Early post-op infection in cemented well fixed THR

- success = 75% 


2.  Early post- op infection in uncemented 

- worse results

- due to lack of cement obstruction

- required 2 stage revision if no bone ingrowth


3.  Acute haematogenous

- only 50% success 

- often immunocompromised


4.  Chronic late

- poor results 

- window of opportunity lost


3. One-Stage Revision


Infected THR Pre One stage revisionInfected THR Post One Stage Revision





- remove prosthesis, debride and replace at single sitting

- lower success rate than two stage

- usually indicated in older, more frail patient

- meticulous debridement critical

- treat infection like cancer





- late onset



- healthy host



- sensitive organisms (gm+)



- no sinuses / good wound

- adequate bone stock




Debridement all necrotic and infected tissue

- removal of implants and all cement

- aided by extended trochanteric osteotomy

- wash +++

- re-drape, new instruments


Reimplant cemented polished femur and all poly cup

- must use ABx PMMA

- already has tobramycin in it

- add powder form vancomycin 

- 2-3 gram in each packet of cement

- each vanco vial is 0.5g

- femur and acetabulum


Can implant poly liner from uncemented acetabulum only

- more ABx cement can be impregnated

- large head for stability


Post operative

- IV Ab's 6/52


Antibiotics must be

- thermostable (excludes tetracycline & chloramphenicol)

- powder form (not genta)

- low allergenic potential

- elute from the cement

- effective against the infecting organism

- Palacos better as higher surface porosity




80% long term survival


4. Two-Stage Revision


Gold Standard




Chronic late

Acute haematogenous




Improved success rate compared with single stage

- success 90% with ABx cement

- 2 opportunities for debridement




1.  2 procedures required

- difficult for patient between stages


2.  Revision surgery more difficult

- scar formation 

- shortening

- distortion of anatomy


3.  Increased cost / Longer time


First stage


Complete debridement

- removal all implants and cement

- meticulous debridement necrotic an infected soft tissue

- insert spacer


A.  Ball of ABx Cement


Infected THR Cement Ball



- leeches ABx

- maintain space for revison hip



- very uncomfortable

- o mobility benefit to patient

- can cause bony erosion


B.  Abx cement in mould


Infected THR Cement Spacer Fracture



- poor function

- fractures / breaks

- painful

- difficult to mobilise

- can cause further bone loss


C.  Company produced cement spacer



- metal spine

- can dislocate / cause bone loss / cause femur fracture


Infected THR Prostalac SpacerInfected THR Dislocated ProstalacProstalac Femur Fracture


D.  All poly liner and cemented stem


Infected THR Kiwi Hip Spacer


Concept of the "kiwi" hip

- +++ Abx cement

- cheap polished femur loosely cemented in

- uncemented poly liner to increase cement load in acetabulum



- stable construct

- patient can mobilise

- no rush to revise



- cost


E.  Antibiotic Coated Nail


Infected THR NailAntibiotic Coated Nail


Second Stage



- Abx minimum 6/52

- at least 2 - 4 weeks off ABx

- consider hip aspiration

- normal CRP / ESR

- intra-operative FFS at time of surgery


5. Three stage Revision


A.  Remove implants - 4-6/52 Abx

B.  Bone graft defects - 3-12/12

C.  Revise components when graft incorporated


6. Resection Arthroplasty (Girdlestone)


Described in 1928 for TB


Infected THR GIrdlestones



- medically unfit for further revision surgery

- refusal for further revision surgery

- sepsis control / virulent bug

- unrevisable due to bone loss

- unlikely to become mobile




Effective control of infection (95%)




Poor function

- pain

- limp

- require walking aid

- 5cm average LLD

- increased energy expenditure 250%


Leaves pateint with nearly useless pseudoarthrosis

- weight bearing almost impossible

- severe shortening

- consider only as last resort


Post operative

- used to recommend 6/52 traction

- makes no difference


7. Amputation



- hip disarticulation




Life-threatening infection

Severe loss of ST & bone stock

Vascular injury




Performed in 0.1%




Intra-operative Fracture

THR Acetabular Fracture




Increased incidence with press-fit component

- especially if under ream




Don't under-ream >1mm


In osteopenic bone 

- line to line reaming

- i.e. ream to outer diameter of cup


This also avoids leaving gaps at floor 

- very common if under-ream by 2mm


Management Intra-operatively


Intra-operative undisplaced fracture + Stable cup

- 2-4 screws through cup

- TWB 2-3 months


Intraoperative displaced fracture

- remove cup

- plate posterior column if factured

- screw fixation anterior column

- additional screws in cup

- +/- antiprotrusio ring                    

- TWB 2-3 months


THR Fractured AcetabulumTHR Fractured Acetabulum 2THR Fractured Acetabulum 3


Diagnosis Post operatively


Can be difficult to diagnose & image

- if unexplained groin pain post-op & press-fit cup 

- look for fracture with multiple oblique views etc

- CT

- may see callous formation


THR Intraoperative Acetabular Fracture


Post-operative early


1. Non or minimally displaced

- recognised immediate post-op

- TWB 3 months


2. Displaced fracture unstable

- ORIF & revise cup


Post-operative late


Peterson & Lewallen JBJS Aug 1996


Type 1

- cup clinically & radiologically stable

- no treatment


Type 2

- cup unstable

- revise as above


THR Femoral Fracture


THR Femoral Intraoperative FractureUncement Femur Intraoperative Fracture




Increased incidence with press-fit components

- act like splitting wedge


Fracture may occur during


1. Dislocation

2. Reaming or broaching

3. Impaction of component

4. R/O cement or old components 




During dislocation


Beware in elderly, osteoporotic patient and in revision

- adequate exposure

- only 1 person manipulate femur


If difficult dislocation

- complete ST release

- removal of acetabular osteophytes

- ankylosed joint or protrusio, division of neck in situ & piecemeal removal of femoral head


During femoral preparation


Pre-op templating of component size

- use of reamers before broaching to remove endosteal bone

- gentle broaching with pause if failing to advance

- sufficient broaching for easy prosthesis insertion


Avoid creation of stress risers i.e. cracks, defects, windows


If cracks or defects created

- bypass with implant by 2-3 cortical diameters distally

- minimise cement extravasation as prevents healing of defect

- use cerclage wires to prevent propogation of fracture


During component insertion

- gentle impaction with pause if failing to advance

- uncemented components often 1 - 2 mm proud of equivalent sized broach




Vertical split not beyond LT

- cerclage wire


Vertical split beyond LT 

- cerclage wires

- longer stem


Perforation of shaft

- bypass defect

- fixate with plate





Investigation of Pain









Thigh pain in uncemented

- micro motion at distal end of stem

- modulus mismatch


Stress fracture / insufficiency fracture

- pubic rami, sacral


Intra-operative fracture


Prosthesis failure


Subtle instability




Muscular tendonitis

- irritation of Psoas

- stretching of Adductors

- vas lateralis herniation


Trochanteric bursitis / tear G medius


Non-union of Trochanteric Osteotomy


THR GT Nonunion




Lumbar / Knee / Pelvic / Abdominal pathology




Nature of Pain


°Pain-free interval  

- indolent infection

- pathology elsewhere (pain same as pre-op)

- poor implant fixation

- impingement


Pain-free interval 

- loosening

- infection

- implant failure


Mechanical pain 

- loosening


Start up pain

- pain with initial movement

- recedes as implant settles

- loosening symptoms


Rest pain / night pain 

- infection

- tumour




Buttock / groin pain 

- cetabular pathology


Thigh / knee pain 

- Femoral pathology


Pain over GT suggests

- trochanteric bursitis / tear G medius

- Non-union of trochanteric osteotomy


Pain in other locations 

- spinal stenosis 

- knee OA 


Radiating below knee

- radiculopathy




Drainage postoperative suggests +++ infection if > 1/12 post-op

History of bacteraemia suggests infection

Prolonged in hospital ABx treatment




Pain with ROM 

- loosening - extremes of motion

- infection - pain throughout motion

- implant failure


Tenderness over GT



- induration, erythema & drainage


Spine, knee & vascular  exam


Groin for inguinal hernia






1. May be normal in face of pathology

- serial comparison very important


2. Difficult to differentiate infection v loosening on XR




Infected THR Endosteal ScallopingInfected THR Periosteal New Bone


1. Radiolucent lines

2. Focal Osteolysis with Endosteal scalloping

3. Periosteal new bone 

- almost pathognomonic

- usually at junction meta / diaphysis on medial side

- only seen in 1-2%




Easier to identify loosening in femur than acetabulum

- femur 90% accuracy

- acetabulum 65% accuracy


Lucent lines don't necessarily represent problem

- may be present in well-fixed prosthesis (retrieval studies)

- due to remodelling




Little value

- increased in 15%

- raised only if sepsis +++




> 30 mm = 80% sensitivy & specificity for infection



- takes 6 - 12 / 12 to normalise post OT

- very non specific, increased in RA and remote pathology

- can be raised in aseptic loosening




> 10 mg/l = 90% sensitiviy & specificity

- rarely increased with loosening


More predicable response post OT

- peak 2/7 (~400)

- normal after 3 /52


In the absence of other causes of elevation


If CRP is negative can be confident is no infection

- negative predictive value 99%


If CRP is positive is still a 20% chance that is no infection

- positive predictive value 75%


IF both ESR > 30 and CRP >10, 84% probability of sepsis


Te99 Scan


Bone scan may show increased uptake from

- infection

- loosening

- HO

- Paget's

- stress fracture

- large uncemented stem (modulus mismatch)

- tumors




- pathology unlikely if negative



- very sensitive

- poor specificty

- doesn't differentiate cause


Lieberman et al JBJS Br  1993

- no benefit of NMBS over x-ray in diagnosis of infection or loosening


Residual activity 



- majority return to normal by 1 year

- 20% remain hot at portions of stem / GT / LT past 1 year



- can remain hot for 2 years 

- can remain hot at distal stem for many years


Infected prosthesis


All phases increased & usually diffuse in 3 phases

- highly suggestive of infection

- can get focal uptake similar to loosening but rarer


Loose prosthesis

- localised increased uptake on delayed phase only

- motion of prosthesis causes increased bone turnover due to bone resorption 

- increased uptake @ GT & LT alone may be normal post op change

- well advanced loosening can show diffuse uptake as for an infected hip


THR Bone Scan NormalTHR Hot Cup Quiscent Femur


Stress sites 

- will see localised area of uptake on scan

- corresponds with cortical thickening on plain XRs


Insufficiency fracture

- occur in osteopaenic patients

- pubic rami fractures may cause groin pain

- sacral fractures may cause posterior hip pain


Indium 111 Labelled WC Scan 


Uncertain role 

- expensive, difficult 

- have to harvest WC


More specific for infection

- especially when combine with bone scan

- sensitivity 92%

- range specificity 75 - 100%




THR Aspiration



- no Abx >4 weeks

- II control & with contrast / confirm in joint

- no LA (bacteriostatic)

- aspirate hip joint x 3 specimens

- if only 1 specimen positive then repeat


If dry, inject normal saline & aspirate 

- controversial


> 65% PMN infection likely

> 1600 white cells microlitre




Harris & Barrack JBJS 1996

- 2% positive rate if aspirate all hips

- therefore be selective


Lachiewicz et al JBJS Am 1996

- hip pain and elevate ESR

- 92% sensitivity & 97% specificity




Crawford et al JBJS 1998

- 95-100% sensitivity

- ff good results from LA expect same from THR

- demonstrates that the pain is from the hip


Intra-Operative Frozen Section


PMN Cell Count 

- 40x power, count white cells in that field

- average over 10 fields


Mirra 1976 > 5phpf

- 84% sens, 96% spec


Lonner 1996 > 10phpf

- 84% sens, 99% spec


Intra Operative gram stain & m/c/s


Gold Standard

- 10% false positive

- Gram stain sensitivity < 20%, but very specific


All revisions no antibiotics for 4 weeks prior


Surgical Opinion


Sensitivity 70%

Specificity 85%






Xray N / Scan N / ESR & CRP N

- not infected

- explore extrinsic causes


Xray Loose / ESR & CRP raised 

- infected

- 2 stage revision with intra-operative M/C/S


Xray normal / Hot scan / Raised ESR & CRP 

- infected

- 2 stage revision

- intra operative FFS to confirm


Xray / Scan / ESR / CRP all equivocal 





Leg Length Discrepancy



Most common reason for litigation against orthopaedic surgeons in THR

Usually from lengthening


Complications of LLD


1.  Nerve palsy


Sciatic nerve - tolerate average 4.4cm lengthening


Common peroneal nerve - tolerate average 2.7 cm lengthening


Lengthen by up to 15-20% of the resting nerve length

- but in reality is unknown and multifactorial


2.  Lower back pain / scoliosis


THR LLDTHR LLD with secondary scoliosis


3.  Abnormal gait


2 - 4 cm discrepancy

- significant increase in oxygen consumption

- also risk of falls


Assessment of LLD






Functional LLD

- blocks


Apparent LLD

- umbilicus to medial malleolus


True LLD

- ASIS to medial malleolus


Apparent shortening

- FFD & adduction hip


Apparent lengthening

- abduction contracture 

- scoliosis, fixed pelvic tilt




Very important

- must mention LLD


X-ray Assessment


AP pelvis 

- both femurs IR 15o

- compensate for anteversion




THR Template LLDTHR Leg Length Ischial LineCentre of Rotation Ranawat Method


1.  Establish Centre of rotation


Acetabular Templating

A.  Ilioischial line / Inter-tear drop line / Superior edge acetabulum

B.  Ranawat

- intersection of ilioishial and shenton's

- 5 mm laterally

- 1/5 pelvis up and 1/5 pelvis in

C.  Rule of thumb

- 2 cm horizontal and 4 cm vertical from teardrop


2.  Calculate LLD

- draw line LT / ischial tuberosity / inferior teardrop

- up to centre of femoral head / centre of rotation

- beware adducted hip on x-ray / false shortening


LLD with hip adduction


3.  Femoral Templating


A.  Size implant

B.  Determine offset

C.  Determine femoral osteotomy from lesser trochanter to restore LLD




1.  Leg to leg comparison


Careful patient positioning

- ASIS perpendicular to floor and patient stable

- ability to palpate both knees and feet

- small pillow to prevent adduction of superior leg

- feel LLD before surgery in this position

- upper femur often feels 1 cm short even if no LLD due to adduction

- aim to reduce LLD to normal after reduction of THR at end of case


2.  Intra-operative measurement



- proximal pin in superoacetabular region

- distally diathermy mark in vas lateralis

- calliper measures horizontal distance (LLD) and vertical distance (offset)

- must place leg in similar position each time to measure leg distance


3.  Tests


Shuck test

- distract femoral head from acetabulum

- should be only few mm of shuck with correct tension


Drop Kick Test

- with thigh extended, knee should remain flexed

- if tension too tight, knee will extend



- if hip tension too tight, ROM especially IR / ER / extension is limited




Transient Perception of LLD

- 14% patients

- usually passes

- may have had LLD before which has been adjusted

- will then feel that leg is longer / which is true



- may get back pain



- abductor weakness

- even dislocation




Delay using shoe lift for 6/12

- allows perceived LLD to resolve


Rarely revision surgery is required

- persistent neurological pain

- beware instability





Nerve Injury



Primary THR 1%

Revision THR 3%

DDH  5%


Sciatic nerve 90% of nerve palsy



- femoral nerve


- ulna / radial nerve from positioning







- exposure / sciatic and superior gluteal nerve

- drill reamer / obturator nerve

- spike of cement / obturator nerve



- diathermy

- cement / obturator nerve





- cerclage wires

- anterior acetabular retractors / femoral nerve

- posterior femoral retractors / sciatic nerve



- post op sciatic nerve palsy


Strap / Pillow (COPN)



- LLD > 4cm

- dislocation


Prognosis Nerve injury


Femoral > COPN  > Sciatic

- most have some residual loss

- 80% incomplete recovery over 18 month period

- none after this


Good prognostic signs

- retention of motor function

- recovery of motor function initial few days


Document neurological status prior to indexed procedure


Poor prognostic signs

- nil recovery by 7 months

- causalgia

- elderly

- poor medical condition

- DM, alcoholism

- spinal stenosis (double crush)

- smoking, steroids


Superior Gluteal Nerve



- L4/5 S1

- sciatic notch above piriformis

- runs between G. medius and minimus

- supplies G. medius and minimus & TFL



- anterior / SP approach injure branches to TFL

- lateral / Hardinge approach respect safe zone in G. medius 3-5 cm proximal to GT


Obturator Nerve



- L2-4 posterior division

- along sacral alar

- emerge obturator foramen

- sensation to medial thigh

- adductor muscles



- screws / cement / reamers / retractors

- antero-inferior quadrant of acetabulum


Sciatic Nerve



- most frequently injured nerve

- 1.5%




L4/5 S1-3

- emerges at G. sciatic notch

- usually tibial and peroneal components combined

- below piriformis

- below gluteals and above short ER



- can be in tibial and CPN divisions

- one or both divisions can run through piriformis

- both emerge above pirifomis

- always treat pirifomis with care in posterior approach


Runs over long head of biceps femoris under gluteal insertion

- passes between LHB and adductor magnus

- SHB only thigh muscles supplied by CPN component



- CPN: DF and evertors

- Tibial: PF and invertors



- Sural: medial sural from tibial / lateral sural from CPN

- Superficial and Deep Peroneal nerve

- Tibial nerve





- > 4cm lengthening in DDH 30% nerve palsy

- 0% if less than 4 cm



- posterior retractors / posterior acetabular wall

- post operative haematoma (CT scan)

- wires or cables (around femur)

- sutures (in closure at end of case)


Direct laceration

- revision surgery

- posterior approach

- DDH, Protrusio (nerve in abnormal position)




CPN division


More vulnerable than Tibial branch

- fixed at fibular head

- more superficial than sciatic nerve

- less surrounding connective tissue




Sciatic nerve / CPN only / Tibial nerve only (very rare)




Determine if CPN at level of hip or knee

- function of short head of biceps




Explore if cause is haematoma

- delayed onset or late progression of palsy in setting of haematoma 

- CT may be useful to diagnose


Explore if believe major direct injury

- transection or entrapment in cerclage wires

- sutured


Otherwise few indications to explore


Femoral Nerve





- enters femoral triangle between psoas and iliacus

- power to quadriceps

- sensation to medial thigh and calf





- anterior retractors above psoas in anterior approaches to the hip

- iliacus hematoma / bleeding tendencies


Femoral nerve blocks



- cement extrusion / screws AS quadrant




Anteromedial numbness

Difficulty climbing stairs




Very rare 0.4%

- usually recovers in full






Periprosthetic Fracture

TypesTHR Periprosthetic Fracture



- incurred during operation


Post operative

- related to osteolysis / trauma / infection


Follow up


1994 National Institutes of Health Consensus on THR


Regular radiographic follow-up to avoid massive osteolysis & fracture






0.6% cemented

0.4% uncemented




2.5% cemented revision

1.5% uncemented revision




1. Bone damage at insertion

- eccentric reaming

- perforation

- fracture


2. Osteolysis


3. Trauma


4. Infection


5. Osteoporosis


Vancouver Classification


Type A (4%)


Avulsion GT or LT


A1 Stem well fixed

A2 Stem loose


Type B (87%)


Fracture near stem tip or around stem


B1 Stem well fixed (20%)

B2 Stem loose (44%)

B3 Stem loose with marked osteolysis (36%)


Type C (10%)


Fracture distal to tip




Most important is whether prosthesis is stable

- if loose requires revision


Type A


Avulsion GT or LT





- undisplaced - no treatment required

- ORIF GT if displaced > 2.5 cm / disruption to abductors


THR Periprosthetic Type A THR Periprosthetic Fracture A PlatingVancouver A Displaced GTVancouver A GT Wire Fixation



- cerclage LT if large and supportive


Type B1 


Fracture around stem, likely well fixed


THR Periprosthetic Fracture B1THR Periprosthetic Fracture B1 Lateral




1.  ORIF with cable plate + proximal unicortical locking screws +/- Cortical strut graft


Cable plate alone

- 90% union


Locking Cable plate + single strut graft

- 98% union

- distal bicortical screws

- proximal unicortical screws supplemented with cables


Cortical Strut Graft


2.  Long stem revision




THR Periprosthetic Revision Long Cemented FemurTHR Periprosthetic Revision Cemented Femur 2




THR Periprosthetic Fracture Type B1THR Fracture Long Stem Revision


Type B2


Fracture around stem, femoral component loose


THR Periprosthetic Fracture B2Periprosthetic Fracture Vancouver B2




Long stem revision

- distal fit (cemented / uncemented)

- must bypass distal extent of fracture by at least 2 cortical diameters


THR Periprosthetic Fracture B1 Long stem cemented revision


May in addition use

- cable plate + unicortical locking screws

- 1 x strut allograft

- autogenous BG + BMP to fracture site


Revision THR Periprosthetic Fracture Uncemented Stem Strut GraftRevision THR Periprosthetic Fracture Uncemented Stem Strut Graft 2Revision THR Periprosthetic Fracture Uncemented Stem Strut Graft 3Revision THR Periprosthetic Fracture Uncemented Stem Strut Graft 4


Vancouver B2 PFFRevision PFF with Modular Uncemented and Strut Allograft


Type B3


Fracture around stem with marked osteolysis


THR Vancouver B3 APTHR Vancouver B3 Lateral




Young patient

- segmental allograft / prosthesis composite



- tumour type proximal femoral replacement


Type C 


Fracture distal to tip of stem




1.  ORIF Cable Plate

- can use MIPO

- overlap femoral stem to avoid stress riser


THR Periprosthetic Type C Plating


2.  ORIF Cable Plate + cortical strut graft


2.  Strut allograft alone

- use 2 x 1/2 femurs fresh frozen

- span fracture 10cm above & below

- 4 wires above & below

- preserve blood supply to linea aspera

- autogenous graft to fracture site


THR Consent


THR Complications




Infection (1% risk deep infection)

Wound Haematoma

Bleeding / Transfusion

Dislocation (2 - 3% recurrent)



DVT/PE (Fatal PE 1/1000 with chemoprophylaxis)

LLD (average 1cm, stability more important)

Medical complications

- pneumonia, UTI, CVA. IHD





Limp (LLD, 1 year with anterolateral approach)

Loosening / Revision (95% 10 year survival)

HO (1% Problematic)

Thigh pain (uncemented stems)

Continued pain

Thigh Pain Uncemented Femur




- up to 4%




Focal pain

- typically anterolateral thigh

- often tender

- corresponds to tip of stem




1.  Instability



- early

- late / failed bony ingrowth



- micromotion at distal stem

- disadvantage of proximal coating


2.  Mismatch modulus of elasticity


A.  Component material

- mismatch between femoral component and surrounding bone

- lower with titanium stems compared with cobalt chrome stems

- titanium components less stiff & tend to have lower incidence of thigh pain


B.  Stem size

- more commonly seen in larger stems

- increases relative stiffness of stem compared to bone


3.  Stem design

- distal flutes can decrease distal stiffness

- fully porous coating decreases incidence, but increases proximal stress shielding


4.  Osteoporotic bone

- more commonly seen with lower bone quality





- start up pain







- migration

- progressive radiolucent lines

- abscence of spot welds


Bone Scan


No correlation of findings with thigh pain




Non operative


Up to 2 years

- allows for remodelling







1.  Cerclage wire cortical strut grafts



- improve bony rigidity over distal stem



- application to lateral femur

- overlap tip proximally and distally 8 cm

- must get host bone integration

- periosteal elevation / bone graft / rigid fixation

- TWB 6 weeks post op



- good results reported


2.  Revision






Vascular Injury

Vessels at risk


Extra-pelvic blood vessels


Femoral Artery



Profunda Femoris

Obturator artery


Intrapelvic vessels


External iliac artery and vein

Obturator artery

Superior and inferior gluteal


External Iliac Vessels



- anterior division of common iliacs / L5-S1

- runs down medial border of Psoas

- some psoas between EIA & intrapelvic surface of anterior column

- EIV accompanies EIA









Screws may penetrate VAN

- can be delayed diagnosis

- significant intrapelvic bleeding may occur before diagnosis

- AS quadrant: minimal protective ST interposition and often poor bone stock

- vein more at risk than artery


CementIntrapelvic cement THR



- heat

- kinking or occlusion from bolus

- erosion from spicule

- avulsion secondary to removal


Avoid cement intrusion into pelvis with wire mesh 


Removal of intrapelvic cement

- required in revision for infection

- define NV relationships

- angiography / MRA preoperatively

- may require separate intrapelvic exposure

- alert general surgeons / vascular surgeons


Femoral blood vessels


Most commonly injured



- common femoral artery is continuation of EIA as passes under inguinal ligament

- passes anterior to hip capsule

- separated from it by psoas




Anterior retractors / dissection

Anterior quadrant screws and drills


Obturator AV




VAN traverse lateral wall together

- separated from quadrilateral plate by obturator internus

- lie at superolat aspect of obturator foramen

- exit pelvis via obturator canal




Screws in AI quad

Retractor under transverse acetabular ligament




Bleeding at inferior transverse ligament

- can be very difficult to ligate

- pack with swab

- hold swab with inferior retractor

- finish acetabulum

- will usually be controlled


Other option is to embolise if still bleeding


Superor Gluteal BV




Branch Posterior Division IIA

- close to posterior column

- exits greater sciatic notch above piriformis




Screw near sciatic notch


Inferior Gluteal & Internal Pudendal AV




Branch anterior division IIA

- exit pelvis between piriformis & coccygeus

- close to posterior column near ischial spine

- internal pudendal artery re-enters pelvis through lesser notch

- IGA pass under piriformis




Very long screws through posterior column


Management on table torrential bleeding


Pack wound, tell anaesthetist & vascular surgeon & obtain proximal & distal control


Notify anaethetist


IV fluids

Coags,  FBC, platelets,  cross match

Transfuse blood

Organise cell saver


Control bleeding


Pack & wait

- uncontrollable, get proximal control


Call Vascular surgeon


Ilioinguinal approach

- clamp IIA, vessiloop IIV


Retro-peritoneal approach

- Rutherford-Morrison incision

- retroperitoneal approach



- angiography

- transcatheter embolisation



THR Difficult

Arthrodesis Conversion



Severe LBP 

- most common indication


Ipsilateral knee pain

- less beneficial



- especially abduction




Absent abductor mechanism


Active infection

Insufficient bone stock






Assessment abductor function


1.  Palpation whilst asking patient to contract

2.  MRI




1.  Difficulty prepping & draping


2.  Exposure

- identify sciatic nerve

- perform GT osteotomy

- may require adductor & psoas tenotomy


3.  LLD

- maximum 4cm lengthening 

- use ASIS pin as LLD guide




Hip Fusion 1Hip Fusion THR 1


Hip Fusion 2Hip Fusion THR 2


Hip Fusion 4Hip Fusion THR 4


Hip Fusion 5HIp Fusion THR 5




Joshi et al JBJS Am 2002

- 208 hips converted at average 51 years

- average follow up 9 years

- 83% good to excellent function

- 96% 10 year survival

- 15 nerve palsies






Sciatic nerve palsy


Residual LLD

Poor abductor function




ConceptTHR Dysplasia Subtrochanteric Osteotomy + Mesh Impaction Bone Graft


THR in dysplastic hips has a higher failure rate

- due to anatomic abnormalities

- due to generally younger age




Restore normal biomechanics and preserve bone stock




Soft tissues


Sciatic nerve in abnormal position / danger

Hamstring  / adductors / RF tight

Horizontal abductors - function less efficiently

Thick hourglass capsule

Thickened psoas tendon




Low subluxation

- shallow with wide opening

- small

- deficient anterior / lateral / superior

- better bone stock posteriorly


DDH Anterior Acetabular Insufficiency


High dislocation

- small pelvis

- thin & soft acetabular wall

- gross anteversion




Increased anteversion

- valgus neck shaft angle


Narrow tapered femoral canal

- tight isthmus

- AP diameter > ML


Posterior displacement of the greater tuberosity




Can be very short

- maximum sciatic nerve can be lengthened is 4 cm


Crowe Classification


Based on extent of proximal migration of femoral head compared to the height of the undeformed femoral head

- femoral head is 20% height of pelvis

- measure the vertical distance between the inter-teardrop distance and the head neck junction

- this distance as a ratio of the femoral head


Crowe I:  Proximal displacement < 50% femoral head (10% pelvis)


DDH Crowe 1


Crowe II:  Proximal displacement femoral head 50-75%                            


DDH Crowe 2Crowe 2 DDHCrowe 2 DDH Lateral


Crowe III: Proximal displacement femoral head 75 - 100%


DDH Crowe 3DDH Crowe 3DDH Crowe 3 Lateral


Crowe IV:  Proximal displacement femoral head >100% (20% pelvis)


Efekhar Classification


A Elongated dysplastic acetabulum

B Intermediate acetabulum

C High false acetabulum

D High but no false acetabulum




Pelvic tilt

Lumbosacral flexibility

Fixed hip deformities

Real and apparent LLD

Previous scars


Operative Management




Restore hip centre

Acetabular bony coverage

Restore LLD


Technical Factors


Soft tissue release

- capsule / psoas / adductors / abductors

- abductor slide or release from ilium

- protect sciatic nerve



- need small components

- restore centre of rotation / bring down to true floor

- may need to augment superolateral acetabulum



- small components

- correct femoral anteversion

- restore offset as best able

- may require trochanteric slide



- > 4 cm need femoral osteotomy


Acetabular component




1.  Restore normal hip centre

2.  High hip centre

3.  Medialise cup 


Restore normal hip centre


A.  Recreate centre of rotation


Place in true acetabulum

- transverse ligament is anatomical landmark


Template hip centre

- inter-tear drop line is inferior margin

- ilio-ischial line is medial margin

- superior edge acetabulum lateral margin


B.  Need for augmentation


Superior defect must be < 30%



- bulk femoral head autograft

- mesh + impaction bone graft

- reinforcement rings / cages

- augmented cups


Acetabulum Reconstruction


Bulk Femoral Head Autograft 


DDH Bulk Femoral Head Autograft



- restore hip centre

- improve bone stock for revisions



- fashion femoral head into 7 graft

- screw into place with 2 x 6.5 mm cancellous screws

- ream into inferior aspect of graft


Spangehl et al JBJS Am 2001

- 44 hips followed up for 7.5 years

- femoral autograft with uncemented cup

- 4 revisions / 10%

- acceptable early results


Harris JBJS 1997

- 55 autogenous bulk autograft + cemented acetabulum

- average follow up 16.5 years

- average age of patient at time of surgery 42 years

- average size of acetabulum 40mm

- average coverage of cup by graft 49%

- 29% (16/55) revised and further 31% (17/55) radiographically loose

- those grafts 30% or less of cup coverage were well fixed at 16 years

- the greater the coverage of bone graft initially, the greater the rate of late revision

- most hips did well for initial 5 - 10 years


Mesh + Impaction Bone Grafting


DDH THR Rim Mesh Allograft


Reinforcement ring / cage + bone graft



- morcellised bone graft

- support with acetabular reinforcement ring

- usually screwed into ilium and ischium

- cement acetabular component into ring


Muller JBJS 1998

- 87 hips, majority Crowe 3

- Muller acetabular roof reinforcement ring

- autograft and cemented polyethylene cup

- 10% revision at 9.4 years


Ganz J Arthroplasty 2005

- 33 cases at 10.8 years

- 3 revisions (9%)

- 2 of the revisions had structural allograft


DDH augmented cups


High Hip Centre


DDH THR High Hip Centre



- allows coverage by native bone

- decreases need for femoral shortening



- very small acetabular component

- very thin poly

- abnormal hip biomechanics

- risk of bony impingement 

- may lateralise hip centre




Kaneuji et al J Arthroplasty 2009

- 30 hips followed up for 15 years

- mild superior hip centre compared to contralateral normal hip (13 mm average)

- 1/30 revised


Socket medialisation / acetabuloplasty / medial protrusio technique



- controlled medialisation with deliberated over-reaming

- can deliberately fracture medial wall



- improves lateral coverage

- decreases JRF through medialisation



- loss of medial bone stock compromising future revision

- risk of early catastrophic component migration medially into pelvis








Small and narrow

Excess anteversion




Small components




Need to be modular


A.  Abnormal shape of proximal femur

- difficult to obtain press fit / risk fracture

- diaphyseal press fit

- small modular metaphyseal component


B.  Need modularity to adjust anteversion

- SROM prosthesis

- dial in version


Cemented DDH prothesis



- smaller with minimal metaphyseal flare

- this allows stem to be orientated independently of patients anteversion


LLD / Abductor Tension




Only lengthen sciatic nerve 4cm

Abductors very tight and prevent lengthening

Difficulty reducing hip


Difficulty reducing hip


1.  Psoas release

2.  Subtrochanteric osteotomy

3.  GT osteotomy


Tight abductors


Trochanteric slide allows

- acetabular exposure

- retensioning abductors

- reposition abductor insertion to correct anteversion




Subtrochanteric osteotomy


THR DDH Subtrochanteric Osteotomy



- acetabular exposure (lift up)

- correction anteversion

- shortening femur 



- mark rotation with 2 x small drill holes

- make osteotomy

- transverse osteotomy allows rotational adjustment

- step cut more difficult but gives rotational stability

- insert trial femur proximally

- reduce hip joint

- calculate resection based on overlap of proximal and distal femoral segments

- uncemented or cemented stem

- use bone resected as onlay


Management Algorithm




Crowe I


Mildly dysplastic

- minimal deformity, good bone stock

- small standard cup medialised for coverage

- < 30% uncovering allowed

- small femoral stem


Crowe II / III


Usually very deficient laterally

- due to femoral head eroding acetabulum

- restore hip centre by reaming medially

- then need to provide superolateral coverage

- autograft + mesh / allograft / DDH cup / tantalum


Crowe IV


Usually good bone stock in true acetabulum

- femoral head has not eroded bone

- recreate acetabulum and place small component

- use teardrop and fovea as landmarks




Crowe I/II


Minimal LLD

- sess femoral shortening required

- avoid excessive anteversion based on abnormal femoral neck

- otherwise get anterior instability and loss ER


Crowe III/IV


If greater than 4cm LLD

- need to shorten femur




Decreased tone

- Polio

- Down's syndrome

- spina bifida


Increased tone

- cerbral palsy

- Parkinson's






- case reports only


Down's Syndrome


Acetabular dysplasia not uncommon in this group




Kloschos et al JBJS Br 2002

- 6 patients

- 7 year follow up

- all doing well


Cerebral Palsy




- resection arthroplasty

- pelvic support osteotomy

- arthrodesis


THR offers best pain relief and function




Young patient

- abnormal muscle strength

- spasticity and contractures

- co-operation issues

- functional demand is low




Schroeder et al Int Orthop 2010

- 18 THR in ambulatory patients

- 10 year follow up

- 1 recurrent dislocation

- 3 aseptic loosenings


Parkinson's disease



- poor neurological status

- progressive worsening with dementia

- high risk dislocation




Weber Int Orthop 2002

- no dislocations in 58 primary THR for Parkinson's


Osteogenesis Imperfecta











Multiplanar deformity

- worsend by previous surgery

- may require osteotomy




Dysplasia often present

- not as severe as in DDH




Can be significant




Have been short for long time

- difficult to restore length

- may require trochanteric slide


Perthes OA previous osteotomyPerthes THR



Bilateral Severe Perthes Hip OABilateral Perthes THR





Migration of the femoral head past the medial wall of the acetabulum / ilioischial line 


Centre edge angle > 40o






Otto's Disease

- bilateral in one third

- middle aged females

- pain & decreased ROM early 

- coxa vara & OA common

- ? causally related to osteomalacia


Bilateral Hip Protrusio





- Paget's

- RA

- osteomalacia / OI

- fracture / central dislocation

- septic arthritis especially TB

- hemiarthroplasty

- Ankylosing Spondylitis 

- Marfan's syndrome, malignancy

- Neurofibromatosis


Charnley classification 1978


Defined medial wall of acetabulum as ilioischial line


Grade I  1-5mm                                Grade II  6-15 mm                            Grade III   >15 mm


Hip Protrusio Grade 1                                                               Hip Protrusio Grade 3


Eldstein & Murphy 1983


Medial wall is acetabular line & ilio-ischial line

- men acetabular line 2mm lateral to ilioischial line

- women 1mm medial to ilio-ischial line is normal


Grade Men Women  
I 3 - 8 mm 6 - 11 mm  
II 8 - 13 mm 12 - 17 mm  
III > 13 mm > 17 mm with fragmentation  



Inexorable progression of deformity

- axis of migration is same direction as joint reaction force in stance phase 




Medical Workup


Identify and treat any underlying cause





A.  Skeletally immature 


Triradiate fusion

- can combine with valgising osteotomy


Steel et al JPO 1996 

- 22 patients with Marfan's syndrome

- 12 of 19 restored to normal

- 4 improved

- 3 unchanged


B.  Young adult 


Valgising intertrochanteric femoral osteotomy (VITO)

- patient < 40, minimal OA 

- may delay THR for 10 years


Aim for 20-30° valgus correction

- if neck shaft angle is 130° aim for 155°

- trapezoid shortening to minimise LLD


Lateralization of femur to restore mechanical alignment


Require soft tissue release especially psoas


C.  Middle aged / elderly




THR Protrusio




Place hip center anatomically 


Restore joint biomechanics

- outcome depends on cup position

- adequacy of correction of the deformity & biomechanics correlates with long-term prosthetic survival

- medial joint positioning leads to high medial stresses




Ranawat JBJS Am 1980 

- 35 hips with protrusio secondary to RA

- 16 of 17 THR >10 mm from hip centre loosened

- 13 THR with <5 mm out good survival


Determine Hip Centre 


1.  Teardrop

- average 2 cm vertical & 4 cm horizontal from teardrop

- average coordinates reported in normal adults 14 mm vertical & 37 mm horizontal


Hip Protrusio Teardrop Method Centre Rotation


2.  Ranawat Method 


Hip Protrusio Ranawat Method Centre Rotation


Draw parallel horizontal lines at the levels of the iliac crests and ischial tuberosity and mark 3 points

- Point 1: 5mm lateral to intersection of Shenton's and Kohler's lines

- Point 2: located superior to point 1 by a distance 1/5 of the pelvic height

- Point 3: similar distance horizontally from vertical line


Isosceles triangle between 1/2/3 locates the acetabulum 

- line 2/3 through subchondral bone


Management Bone Defects


1.  Assess medial wall integrity with CT


Hip Protrusio CT Medial Wall IntactHip Protrusio CT Medial Wall Intact 2


2.  Algorithm / Ranawat J Arthroplasty 1986


A.  < 5mm - no graft required


Hip Protrusio Grade 1THR Protrusio Type 1


B.  > 5mm but medial wall intact - morcellised bone graft


Hip Protrusio Type 3THR Protrusio Medial Morcellised Bone Graft


C.  No medial wall - mesh / cage + morcellised bone graft





- template LLD (max 4cm)

- define acetabular defect with CT

- ensure intact medially




1.  Sciatic nerve is nearer the joint than normal

- identify and protect early


2.  Dislocation of the hip can be difficult

- femoral osteotomy in situ + femoral head removal piecemeal may be required

- trochanteric osteotomy may be required for exposure



- enlarge rim only

- avoid creating peripheral defect


Contained acetabular defect


Morcellised bone graft

- rim fit uncemented cup

- cemented cup


Uncontained acetabular defect


A.  Wire mesh / bone gaft / cemented cup

B.  Wafer bone graft / morcellised bone graft / cage / cemented cup



THR Primary

Background & Technique

IssuesTHR Uncemented





Bearing Surface

Head Size





Disabling hip pain

Severe functional impairment

Failed non operative management


Not Indicated 


Painless deformity






1° OA


2° (accounts for maybe 50% OA hip)


Secondary OA




Hip OA Post SUFEBilateral SUFEHip OA Post Sufe 2




DDH Crowe 1




Hip OA PerthesHip OA Perthes 2Hip OA Perthes 3Hip OA Perthes previous osteotomy




Hip OA post Acetabular FractureHip OA post displaced Acetabular FractureHip OA Post NOF FractureHip OA post subcapital fracture




Hip OA PagetsPagets Bone Scan  




HIp OA Bilateral AVN


Coxa Vara                                                                                                                     


Hip OA Coxa VaraHip OA Coxa Vara 2                                              




Hip OA Post Sepsis







1.  Five Absolute


Active infection


Flail / Neuromuscular impairment


Inadequate soft tissue cover


2.  Five Relative


Young patient

Heavy demand


Poor compliance

Poor mental state


Pre-op Evaluation



- mobility

- life expectancy

- fitness for anaesthetic - ardiopulmonary

- urinary status / TURP before THR

- teeth

- NSAID / aspirin / plavix / warfarin



- abductor strength


- contractures

- vascularity 

- check skin / scars


Medical workup



- DM / RA / Hemophilia / Marfan's etc


Beware difficult hip



Medical / Anaesthetic Review


CXR / ECG / FBC / UE / Coags / GP&H



- cease Aspirin / Warfarin

- steroids

- diabetic medications


Education & Advice


Informed consent

- infection


- blood transfusion


- dislocation

- fracture

- DVT / PE

- limp

- revision


Rehab starts pre-operatively

- home modifications

- discuss precautions (high chair, pillow at night)

- physio

- driving (usually not for 6 weeks)

- social worker / occupational therapy

- work arrangements








1.  AP pelvis / AP of hip showing proximal femur / Lateral


2.  Lower extremities internally rotated 15° to 20° 

- to allow proper offset templating

- can roll patient if severe OA


3.  Magnification marker

- most XR departments use bulky tray placed in compartment

- 2 inches below table top

- resulting in magnification of 15% to 20%

- degree of magnification directly related to distance from bone to cassette

- obese magnification can be > 25%

- thin patient can be < 15%




Component Position


Leg length 


Neck-shaft angle 


Femoral offset 


Degree of acetabular dysplasia 


Acetabular bone defects


CT scan


Hip OA previous Acetabular fractureHip OA CT Anterior wall discontinuousHip OA Posterior Wall Intact




Fixation - cemented v uncemented


Bearing surfaces


THR Technique



- on side on bed

- pressure area care / CPN / ulna nerve

- pelvis perpendicular to bed

- completely stable

- Charnley hip supports

- able to palpate both knees and feet for leg length

- small pillow between legs / comparable position

- saline bag under armpit

- TEDS / SCDs lower leg




Antibiotics at induction

- broad spectrum: first generation cephalosporin

- allergy: vancomycin / clindomycin

- repeat if operation longer than half life / 2 hours





- Posterior / Kocher-Langenbech

- Lateral / Hardinge

- Transtrochanteric / Charnley 

- Anterior / Smith Petersen




1.  Position of knees

- comparable position

- check LLD prior to incision

- aim to recreate equal LLD

- note:  adduction of superior leg will artificially shorten leg in this position


2.  Intra-operative

- pin in superior acetabulum

- mark on femur

- recheck with femur always in same position

- can measure LLD and offset





- anterior acetabular retractor / beware femoral nerve

- inferior acetabular retractor / beware obturator artery

- avoid posterior retractors / beware sciatic nerve



- remove labrum and capsule

- may need to remove curtain osteophytes

- define true floor with gouge at transverse notch 



- medialise initially to true floor

- medialisation decreases JRF

- to bleeding bone

- preserve anterior and posterior walls


Cemented cup

- ream 2 mm > cup size for cement mantle

- leave transverse ligament intact

- low viscosity cement / Palacos


Uncemented cup

- young ream 1 mm < cup size

- old ream 2 mm < cup size


Acetabular Orientation



- 40+/-10°

- 45o to bed



- 15 - 30°

- increase in posterior approach

- use pelvis as perpendicular to floor

- use inferior transverse ligament


Femoral Stem


Entry point

- bow chisel

- start lateral and posterior

- follow bow of femur

- pass reamers

- find centre of femur

- check not perforating femur 


Incremental increase in broaches



- until broach rotationally stable

- don't wash away good cancellous bone



- leave some cancellous bone

- allows cement interdigitation



- anatomical anteversion 15°

- neutral or slight valgus



- offset / neck length / head size / LLD / stability


Insert definitive component and retrial

- ensure stability / LLD

- apply definitive head



- irrigate to remove particles

- +/- drain

- pressure dressings


Post-operative Management


4 x doses broad spectrum antibiotics

Check Hb and electrolytes next day


Abduction Pillow - 6/52 nightime

TEDS / Compression - 6/52

Anticoagulation - 6/52


Early mobilisation with Physio


Precautions until pseuodocapsule forms

- no flexion >90°  6/52

- limit IR / adduction

- sit in high chair 6/52

- no driving / 6/52

Bearing Surfaces



The removal of material, with the generation of wear particles under an applied load and in relative motion


Tribology is the study of wear and lubrication


Wear mechanisms



- bonding of the surfaces when pressed together

- may pull away material from the weaker surface



- asperities on the harder surface cut and plough 

- remove materials from the softer surface



- repetitive local stresses exceed fatigue strength


Wear Modes


Mode 1

- from motion of two surfaces rubbing together

- as intended


Mode 2

- primary surface against a non intended secondary surface

- head eroded through poly and up against metal backing


Mode 3

- two primary surfaces with a third body

- roughens surface

- increases mode 1 wear


Mode 4

- two secondary surfaces / backside wear

- creates third bodies

- i.e. screw fretting or between liner and metal backing


Wear types


Linear Wear 

- radiographic change in thickness of socket at maximal point of wear  

- based on 2D Xray


Volumetric Wear 

- volume of particulate poly created

- calculated based on trigonometric formula

- in turn based on measured linear wear & square of radius of articulating head

- probably represents underestimation of actual volume of wear particles produced 


Now more sophisticated computer based systems more accurately estimate wear


Fluid-film lubrication


Completely separates surfaces

- when fluid film height is thicker than height of asperities on the surface

- decreases roughness

- decreases wear


Variables in amount of wear


Type of bearing surface 

Head size 

Acetabular orientation






Repeating chain of ethylene monomers



- low cost

- multiple options i.e. elevate rim

- high wear resistance

- no toxicity




Wear particles very bioactive


Factors in Poly wear


1.  Preparation of poly effects longevity 

A.  Machined from extruded polyethylene bar stock 

B.  Compression moulded directly from the polyethylene resin


2.  Sterilisation & Aging

A.  Surface treatment

- ethylene oxide gas

B  Gamma irradiation

- in vacuum causes cross linking which decreases wear

- in air get oxidation which increases wear


3.  Highly cross linked


Occurs when free radicals from a covalent bond between PE molecules



- improved wear resistance

- up to 95% wear reduction compared with normal poly

- ability to use larger head sizes

- normal liner must be 8 mm

- can decrease this thickness to allow larger heads



- decreased yield and tensile strength

- like ceramic, is more brittle with increased wear resistance



- ultra high molecular weight polyethylene


5.  Poly thickness


Thicker poly diminishes stresses in subchondral bone & within poly


Metal heads / CoCr


THR Metal on Poly


Ceramic heads on poly


THR Ceramic on Poly



- Alumina AL2O2

- Zirconia ZrO2



- more difficult to scratch

- reduce abrasive wear



- can be polished to lower surface roughness



- hydrophilic

- improved lubrication and lower friction



- 0.2 mm / yearr on 2D& 3D models

- may be reduced by 50% compared with metal on poly


Ceramic on ceramic




Highest wear resistance

- invitro 0.007mm3 / million cycles

- CoCr / poly 70-90mm3 / million cycles



- excellent lubrication



- can be highly polished


No toxicity




Position sensitivity


Liner chipping

- must take care during insertion


Fracture risk

- was a worldwide recall of zirconia heads in 2001

- due to unexpectedly high fracture rate in zirconia heads from one manufacturer

- now about 1 / 10 000


No hooded liner available


May need to revise ceramic with ceramic

- particles remaining may be hard than new bearing surgace




Trunion damage in revision

- new ceramic head may not lock to new trunion

- can use ceramic head with metal neck augment inside it


Metal on Metal


THR Metal on Metal




Popular in the 1960's

- McKee-Farrar replacements

- abandoned

- partly because of poorer results than Charnley low friction arthroplasty

- partly metal sensitivity concerns


Interest was aroused when it was noticed in some patents very good survival rates at 20 years and beyond

- discrepancy between some patients doing very poorly and some patients doing very well


Second generation design


Important concept of clearance


Difference in radius between the two surfaces

- reducing clearance and producing an exact fit is worse

- creates equatorial contact with cold welding and seizure


Prefer controlled clearance 0.06-0.1mm

- creates polar contact rather than equatorial contact


New machining far superior




Decrease wear


Reduced linear and volumetric wear

- initial run in perior then steady state

- linear wear < 0.003 mm / year



- increase smoothness

- thicker film

- polar bearing not circumferential


Strict control over manufacture essential

- early failures due to poor manufacturing




Very high wear resistance

- 1 / 60 of metal / poly


Large heads

- decreases dislocation / improves ROM / function




Increased ion levels


Serum / blood / RBC / urine increased levels Co & Cr

- up to 500 times the number of poly particles per year

- tends to decrease with time

- effects unknown


Best to measure serum levels in Nmols/l

- range for well functioning implant is 15 - 30 for Co and Cr

- increasing levels or levels several time normal of concern

- can imply a failing implant



- no evidence for this

- metal on metal follow up for 50 years (McKee-Fararr)


Delayed type hypersensitivity


Cause unknown

- lymphocyte reaction

- very rare (1/1000)

- may cause unexplained pain


Patient can get large inflammatory reaction

- can cause tissue destruction +++

- lose abuctors etc

- difficult salvage


AJR 7 years


Ceramic / Ceramic  3.9%

Metal / Poly             3.2%

Ceramic / Poly         4.1%

Metal / Metal           7.7% (Head sizes > 28mm)






Peak pressures during gait

- between heel strike and early mid stance

- increases in both JRF and abductor activity


Chair rising 

- triples pressures


Hip forces


Single Leg Stance / Free Body Diagram of the hip



- force exerted by the abductors

- balance effective body weight acting on the head of the femur

- equal magnitude, opposite direction


Abductor muscle force

- both a horizontal and a vertical component  

- assumed to be oriented at 30° with respect to a vertical axis

- this adds to the forces across the hip



- only G medius tension is calculated 

- a gross oversimplification

- need to consider G max. & other muscles

- ground reaction force is under calculated

- GRF recorded in prosthetic femur is much higher than FBD would suggest




Body weight during one-legged stance 

- 5/6 BW (1/6 BW is weight of leg patient standing on)

- effective body weight will act in a vertical direction


Single leg stance 3x BW

Walk ~4x BW

Jog~ 6x BW

Stumble ~9x BW


Adbuctor lurch


Shifting the body weight over the centre of the hip joint

- eliminating the need for the abductors to balance body weight

- reduce joint reaction force


Impact of walking aids


Walking with cane in contralateral hand

- analytical and in vivo studies 

- clearly shown reduces the joint force



- moment arm of the cane is much larger than that of the abductor muscles

- lower muscle forces are now required to balance the effective BW moment


Implications of rotational moments


Longitudinally and posteriorly directed loads

- most critical in generating stem fractures

- most fractures start at the anterolateral corner.


Posteriorly directed forces

- occur when the hip is flexed

- result in retroversion of the stem

- may play a significant part in loosening femoral stems


Clinical implications of hip joint geometry


Mechanical ability of the abductors are affected by

- head-neck angle

- neck length

- joint centre position



- recreate centre of rotation

- decrease JRF

- increase offset

- Increase abductor strength


Joint centre


Joint forces are minimized when the joint centre is moved medially, inferiorly, and anteriorly

- maximizes the moment-generating capacity of the abductors 


OA displaces femoral head laterally, superiorly, and posteriorly

- largest joint forces and moments are generated in this position


Lateral and distal joint centre 

- decreases the abductor's moment arm 

- therefore preventing contralateral pelvic drop now requires an increased muscle force

- increases the joint's compressive force


Superior joint centre

- inferior functional outcome

- decreased abductor strength

- loss of passive hip flexion

- can compensate with increased neck length   


Higher contact force / increased wear and loosening

- superior and lateral joint centre

- decreased femoral offset

- decreased abductor moment arms 


Head Neck Angle


Varus hip

- decreased head-neck angle 

- increases the mechanical advantage of the abductors

- therefore should minimise joint contact forces

- also improves stability with increased congruence


Valgus Stem

- decreased bending moment or shear on stem

- increased axial stem loading


If excessive

- increases knee valgus strain

- lengthens limb

- superior dislocation


Varus Stem

- increases shear on neck

- decreases axial loading


If excessive

- shortens femur

- increases dislocation


Neck length


Decreasing the neck length 

- similar to increasing the head-neck angle (valgus) 

- compromise the abductor function and increase the joint reaction force



Cemented Exeter Technique

Cemented cup and femur via posterior approachTHR Cemented Exeter


Set up

- on side

- charnley supports posterior on sacrum

- anteriorly on ASIS

- patient slightly tilted backwards

- avoids cup retroversion


Posterior Approach

- identify short ER

- open interval between G medius and piriformis with scissors, insert anterior retractor

- do the same with inferior aspect of quadratus

- diathermy all visible bleeders now

- 2 x stay sutures in short ER with 1 ethibond, clip and cut

- take off short ER and capsule with diathermy, superior radial cut in capsule to labrum

- dislocate hip

- second running stay suture in capsule with Ethibond



- release posterior capsule from short ER to mobilise better as flap for repair

- release superior capsule from labrum, also anterior capsule from labrum delicately with knife

- place specific Exeter anterior retractor

- divide inferior capsule delicately with diathermy, leave inferior transverse ligament intact

- place rolled swab here, place inferior retractor

- anterior retractor is tied to charnley support with weight and chain

- inferior retractor has weight attached, supported by assistant

- insert Norfolk-Norwich retractor superiorly




Remove labrum

- identify floor by removing osteophyte / reaming medially /  or can use 2.5 mm drill and measure floor depth

- ream in increased sized until fits in AP diameter

- need to remove all cortical bone, can do so with smaller reamer

- many drill holes required superiorly, this is the area where good interdigitation is critical and important

- drill holes in ischium and superior pubic rami as per charnley

- dry acetabulum with swabs and peroxide

- place reamings with spoon at inferior acetabular ligament and compress, this prevents cement leaking inferiorly

- trial cup, can use cup with peripheral poly lip to pressurise, cut to size

- insert ball of cement when no longer sticky

- compress till 5 minutes, twist pressuriser to remove

- dry blood with swab on a stick

- insert cup on insertion device

- place inferior cup first, medialise +++, then set closure and anteversion




THR Cemented Exeter Inferior Cement LeakTHR Cemented Cup Excessively OpenTHR Cemented Exeter Medial Cement Penetration


Femoral Stem



- held vertical by assistant

- fish mouth elevator to elevate femur

- gluteal retractor holds gluteals


Entry point

- box chisel

- start lateral and posterior

- follow bow of femur

- pass 2 x reamers

- find centre of femur

- check not perforating femur 


Incremental increase in broaches

- leave some cancellous bone

- allows cement interdigitation



- anatomical anteversion 15°

- in neutral or slight valgus

- >5° varus increases failure

- line up with patella as insert



- offset

- neck length

- head size

- check stability and LLD




1st generation 

- all by hand



- plug, lavage, retrograde fill   



- vacuum centrifuge, pressurisation 



- cement restrictor 1 cm beyond tip

(makes easier to get out if needed)

- wash cancellous bone with water

- H2O2 gauze (lyses RBC), suction

- vacuum centrifuge Abx impregnated high viscosity cement

- baby suction catheter

- retrograde filling with cement gun

- fill at 1 minute

- pressurisation til fat emerges (warn anaesthetist)

- slow insertion stem at 4 minutes, follow lateral wall

- clean cement away

- maintain constant pressure til hard



- ensure stability / LLD

- apply definitive head



- capsule and ER sutures passed through drill holes in GT

- use suture passer


Clinical History






Other joints / other specific


Interventions (surgery, physio, injections)


PMHx / PSHx / Meds / Allergies


Social History

- occupation

- dwelling

- smoking / alcohol




"What is your problem?"




Nature (Sharp or Dull)

Intensity (1-10)

Location - point for me?

Duration - how long?


- specific details of injury ?

- rest / night / start-up

Concomitant Factors 

- locking / clicking / swelling

Aggravating Factors

Relieving Factors


Pattern / frequency


Associated symptoms

- leg lengths

- stiffness


Causal factors 

- AVN -> steroids, alcohol, RTx / CTx

- RA / other inflammatory conditions

- CDH / DDH / SUFE / Perthes


Other joints


Knee / Back

Signs inflammatory condition


Functional Assessment


Lower limb (Modified Harris Hip Score)

1.  Shoes & socks

2.  Stick / Walking aid

3.  Limp

4.  Stairs

5.  Walking time/distance

6.  Public transport / In or out of Car?

7.  Run or Squat if young adult

8.  Prop at speed if sportsman


Little old lady gets out of bed, puts her shoes on, picks up her stick, & limps to the door

- climbs down the stairs, walks two blocks to the bus, & pushes over the jogger doing squats



"What can't you do that you used to be able to do?"


1.  Occupational

2.  Recreational - sports, hobbies

3.  ADL's

- recreational

- showering / toileting / cooking / shopping








Lifestyle modification

- weight loss




Orthotics - stick



- symptomatic (NSAIDS, narcotics)

- disease modifying (steroids, anti-rheumatoid)







Cemented Acetabulum

IndicationsTHR Cemented Acetabulum


Neoplastic / metastatic

Severe osteoporosis






- longevity directly related to quality of cement penetration into acetabulum




Reflection all Poly (S&N)

Exeter all Poly (Stryker)

Zimmer ZCA


Cemented ZCA cup




Retrieval studies from successful THR's

- fibrous membrane found at least in part

- begins at periphery of bone-cement interface 

- mechanical testing shows the most stable are those with least membrane


Metal Backing


Theory that more rigid implant construct could more evenly distribute stresses to surrounding acetabulum 

- cement & subchondral bone would be protected from fatigue failure


Actually perform poorly compared with all poly

- reasons for inferior clinical outcomes not well understood

- accelerated wear of polyethylene suggested as cause




Process of loosening may be result of cellular rather than mechanical process

- determined by host reaction to polyethylene debris



- obvious migration in comparison previous films

- cement mantle fracture

- progressive > 2 mm lucency cement / poly interface

(c.f. cement-bone interface)


Charnley & De Lee - 3 zones

1 - superior 1/3

2 - middle 1/3

3 - inferior 1/3


Cemented Cup 3 Zone LysisCemented Cup Lysis Zone 1




AJR 2010


9 year


Exeter / Contemporary   6.0%

Exeter / Exeter              4.9%

Spectron Reflection        9.0%

MS30 / Low Profile Cup  1.7%


CPT / ZCA 7 year            %2.9



Cemented Femur

THR Cemented Femur

Goals in femoral cementing


Optimize cement-bone interface

Cement mantle free of defects

Minimum 2 mm thickness

Femoral component centred in cement mantle




Swedish Joint Registry


Reflection All Poly / Spectron 92% 10 year


Exeter All Poly / Exeter 93% 14 year




1.  Polished

- Ra less than 1 micrometer

- polished stems create little abrasion

- allow subsidence and keep cement in compressive loading 


2.  Matte 

- Ra less than 2 micrometer

- matte finish will not create excessive abrasion unless stem allows large micromotion 

- allows some mechanical interlock with cement


3.  Rough 

- Ra greater than 2 micrometer

-  expected to cause excessive abrasion


Studies have shown increase aseptic loosening and revision rate with matte finish

- failed ~10% at 10 years

- c.f. 4% at 20 years for polished




Creep is time dependent deformation

- creep of cement is related to age

- creep at 1 day is 3.25 x at 7 days

- creep allows stabilization

- cycles of creep, followed by stress relaxation leads to stem subsidence in the mantle

- Matte finish prevented subsidence




Controversy exists over the use of collared prosthesis

- results in increased load transfer from implant to proximal femur compared to collarless implants


A.  May reduce stress shielding of proximal femur & reduce strain in proximal medial cement mantle


B.  Prevents subsidence


Exeter stem 


Behaves as a Morse taper in the cement mantle

- transmits both torsional & compressive loads

- generates hoop stresses in the cement which allows it to expand slightly




1.  Smooth polished surface

- no sites of stress concentration


2.  Broader laterally than medially 

- helps to diffuse the compressive stress medially 


3.  Tapered shape from proximal to distal 

- allows controlled subsidence within the cement column; 


4.  Cobalt-chromium alloy stems 

- are used in most stems

- generate less particulate debris than titanium implants


5.  Triple taper concept

- femoral component tapers to a point in both the AP and lateral planes

- in addition, the stem is more narrow medially and widens laterally


Advantage low porosity cement

- Cement fails in fatigue

- Centrifugation decreases pore size in cement 

- approximately 200 to 400 nm in diameter 

- results in an increase in cross-sectional area

- 25% increase in ultimate tensile strain 

- 125% increase in tension-compression fatigue strength  

- Similar benefits demonstrated with vacuum mixing


Cement Issues


Cement viscosity

- in vitro and in vivo tests 

- structural superiority of high viscosity over low viscosity cement

- i.e. Simplex (highly viscous) v Palacos (low viscosity)



- strength of cement-bone interface directly related to depth of penetration of cement into bone

- pressurization increases penetration



- achieve more uniform cement mantle 

- especially zone 5 & 6


Cement Mantle


Ideal cement mantle thickness has not been defined

- autopsy studies - crack incidence greatest when mantle < 2 mm

- issues with the varus stem


Varus stem 

- associated with higher incidence of aseptic loosening

- results in thin or nonexistent cement mantle in proximal medial & distal lateral zones



- in relatively small doses effect on mechanical characteristics of PMMA negligible

- must be heat labile

- vancomycin / tobramycin / gentamicin


Cementing techniques



- finger-packing doughy cement 

- no cement restrictor



- cement restrictor

- cleaning with pulsatile lavage  

- cement inserted retrograde using cement gun 



- vacuum centrifuge (reduce porosity)

- pressurization of cement mantle 

- surface modifications on implants 



- stem centralization proximal & distally

- ensure adequate & symmetric cement mantle


Barrack grading system for cement technique


Aseptic loosening correlates with cement technique


A. Complete filling of proximal portion of diaphysis 

- difficult to distinguish cortex from cement

- commonly referred to as "white-out"


THR Type 1 Cemented Femur


B. Near complete filling of diaphysis 

- can distinguish cortex from cement in some areas


Type 2 Cemented Femur


C. Divided into C1 & C2



- Incomplete cement mantle in proximal portion

- > 50% of cement-bone interface demonstrates radiolucencies


THR Type 3 Cemented Femur



- Mantle < 1 mm thick or metal is up against bone


THR Type 3b Cemented Femur


D. Cement mantle with gross deficiencies 

- no cement below the stem, major defects in the mantle, or multiple large voids in the mantle





- need for revision surgery

- clinical failure (a painful arthroplasty)

- radiographic failure (loose implant)


Mechanisms of Failure


Mechanical factors

- debonding between stem & cement initially occurs at cement-metal interface

- produces high peak stresses in cement mantle proximally & near distal tip of stem 

- initiates cement cracks esp areas of thin cement / adjacent to mantle defects / pores initiate & propagate 


Biologic processes 

- then become more important

- particulate polymeric debris gains access to endosteal bone

- stimulates foreign-body reaction 

- bone resorption with fibrous tissue membrane beginning at pseudo-capsule extending along cement-bone interface


Harris Categories 


"Definitely loose"

- migration of prosthesis

- cement mantle fracture


Cemented Femur Definitely Loose


"Probably loose" 

- continuous radiolucent line at cement-implant


Cemented Femur Probably Loose


"Possibly loose" 

- radiolucent line cement - bone


Cemented Femur Possibly Loose


Autopsy studies 


Radiolucencies most commonly related to skeletal remodelling

- not to the formation of soft-tissue membrane between cement & bone

- inner cortex commonly forms adjacent to cement mantle

- not distinguishable from cement on Xray

- 2nd medullary canal forms between inner & outer cortex 

- appears as radiolucency on Xray

- non-progressive


Uncemented Acetabulum

GoalTHR Uncemented


Initial mechanical stability

- adequacy of locking between component and bone


Need initial press fit for mechanical stability

Long term require biological fixation




Can change liner

- multiple revision options i.e. for dislocation


Simple to remove

- Zimmer Xplant




1.   Smooth

- relied on mechanical interlock for stability and long term fixation

- unacceptable early revision rates

- initial press fit, but no biological fixation


2.  Threaded

- universally bad results

- due to small contact area between bone and implant


3.  Smooth HA coated

- improved but still inferior results


4.  Porous coated

- allows ingrowth

- much better results compared to smooth components

- titanium or HA


5.  Hemispherical

- oversized cup

- initial press fit


6.  Flattened hemispherical

- rim fit




1.  Material must be biocompatible

- titanium mesh

- cobalt chromium beads

- HA

- all of these materials have been shown to be adequate provided pore size is correct


2.  Surface must have optimal pore size

- between 100 and 400um


3.  Component must be placed in intimate contact with viable host bone


Press fit

- < 0.5 mm gaps 

- require tight peripheral press fit with complete seating

- maximises surface are available for ingrowth

- maximises area for stress transfer



- 1-2 mm underream

- risks are acetabular fracture and underseating


Acetabular Underseating


4.  Adequate initial stability to allow reliable ingrowth

- micromotion > 40 um generates fibrous tissue 



- press fit with supplemental screw fixation

- line to line reaming with supplemental screws

- spikes

- pegs


Supplemental screw fixation

- 2 x bicortical screws

- provide similar stability as press fit


Uncemented Cup with screws


Screw problems

- can get backside wear / fretting

- holes can provide route for particle wear


Technique Uncemented Cup


Centre reamer in desired hemisphere of acetabulum

- begin 6 - 10 mm below templated size (44)

- medialise initially

- remainder reaming in direction of final component position

- 45o abduction

- 20 - 30o abduction

- increase until contact anterior and posterior

- AP diameter is what determines cup size

- petechial bleeding

- don't take away all subchondral bone

- continually assess posterior / anterior walls - must preserve


Can bone graft base and reverse ream

- especially with flattened hemisphere


Insert component 1 - 2 mm larger

- ensure seating (remove insertion handle and probe base)

- ensure stability

- add screws if any doubt


Screw placement


 Acetabulum Wasielewski Safe Zones


Wasielewski et al JBJS 1990

- anatomical cadaveric study

- line ASIS to centre acetabulum & ischial tuberosity

- line perpendicular to this 

- four quadrants 

- safe quadrants = 2 posterior quadrants

- posterior screws do not emerge within pelvis


Structures at risk


AS quadrant

- external iliac vein > artery

- vessels can be within 0.5 cm of the inner cortex of the pelvis

- become closer with increasing age

- in the anterior quadrants 25mm screws often too large


AI quadrant

- obturator nerve & vessels

- femoral artery 


PS quadrant

- sciatic nerve / superior gluteal nerve & vessels in danger at greater sciatic notch

- aim screw between 2 cortices of ilium

- direct towards SIJ

- can tolerate 85 mm


PI quadrant

- internal pudenal vessels

- inferior gluteal nerve & vessels

- maximum screw length is 25 mm




Acetabular fracture


Increased risk

- > 2 mm underream

- acetabular sizes < 52

- elderly (consider line to line reaming and use of screws, or use cement)



- screws

- posterior column plating

- cage


THR Uncemented Cup Acetabular Fracture


Failure of liner fixation / acetabular fixation


Acetabular spin out

- insufficient initial fixation

- failure biological fixation


THR Uncemented Cup Spin out


Liner spin out

- must ensure fixation method is sufficiently engaged


Errant Screw placement


Anterior quadrants

- can cause catastrophic haemorrhage



- angiogram  / embolism

- laparotomy / pelvic packing




Loosening Uncemented Cup


Can be very difficult to identify with uncemented acetabulum





Uncemented Femur

GoalTHR Uncemented


Initial press fit

- implant geometry fits the cortical bone in the proximal femur

- good initial mechanical stability


Biological fixation for success

- good press fit

- minimal micromotion

- bony or fibrous tissue ingrowth or ongrowth



- avoidance adverse stem bone stiffness ratios

- fixation surface that provides a transitional stress transfer from the proximal femur to the diaphysis

- avoid extreme stress shielding or excessive rigidity


Press fit


True Press-Fit in Bone 


Bone is a viscoelastic material

- implies that its elastic recoil will become less with time

- the amount that bone will "creep" or undergo stress-relaxation depends on its density

- cortical bone has less viscoelastic behavior than cancellous bone

- the fact that bone will relax and lose elasticity over time limits the amount of time over which a true press-fit can be maintained in bone

- once the initial press-fit dissipates,a prosthesis may move under load in the bone and either re-establish a press-fit or become loose


Non porous coated uncemented implants are commonly referred to as press fit implants




Proximal metaphyseal filling

- curved, anatomic stem

- most common

- tight proximal fit


Distal isthmus filling

- straight stem

- used more commonly in revision


Techniques of Initial Fixation


Definition Rigid Fixation

- micromotion <150 microns

- ideal 50-100


A.  'Press fit' (1-2mm undersized) technique

- bone expands around prosthesis

- generates hoop stresses

- femur and acetabulum


B.  Line to line fit

- bone is prepared to same size as implant

- extensive porous coating with stem




Stove pipe femurs (Dorr < 0.75)

Poor bone stock


Proximal femoral geometry / Dorr calcar-to-canal ratio


Important if considering uncemented prosthesis


3 types - 501's, Stove pipe, Flares

- measure canal at LT & 10cm below 

- inner diameter at midportion of LT divided by diameter 10 cm distal

- must be <75% for uncemented prosthesis


Type A 

- ratio < 0.5 

- cortices seen on both AP & lat

- most amenable to uncemented component


Dorr A Femur


Type B 

- between 0.5 and 0.75 

- thinning of post cortex on lateral

- intermediate


Dorr B Femur


Type C 

- > 0.75 

- thinning of cortices on both views 

- "stovepipe" femur

- favours use of cemented stem


Biologic fixation


Two types


1.  Ingrowth 

- porous coating

- HA coated

- combinations


2.  Ongrowth 

- grit blasted

- increases roughness

- typically needs to be entire surface 




Pore size

- optimum pore size 50-350 microns (ideal 50-150)



- 40-50%


Pore depth

- deeper pores better

- increased shear strength with loading


Mechanism of porous coating


Titanium plasma sprayed

- often used to create pores

- then covered with HA to supplement


Tricalcium phosphate

- also used


HA coating

- sprayed on as a porous coating

- osteoconductive

- surface dissolution to Ca and Phosphate

- stimulates osteoblasts


Extent of Porous coating


Complete / incomplete

- both proximal and distal fixation are important

- is a trade off between fixation and shielding


Extensively coated implants

- improve likelihood of solid fixation

- distal loading of bone

- get mainly diaphyseal spot welding

- increase proximal stress shielding

- same problem with cemented implants


Femur Fully Coated Proximal Shielding


Proximal porous coating

- proximal loading of bone

- minimises proximal shielding

- more common






Want less rigidity to minimise stress shielding


Stiffness related to 

- modulus

- fourth power of the stem radius

- solid v slotted / fluted stems


Young's modulus of Elasticity


Bone 12

Titanium 117

Cobalt-chromium 210


Minimise rigidity


1.  Titanium alloy v cobalt chromium

- less structural rigidity

- lower modulus of elasticity

- 2 - 3 x less stiff


2.  Implant size

- as size increases, rigidity increases


3.  Design

- some stems have a coronal slot to decrease rigidity




Engh et al categories


1.  Osseointegration

2.  Stable Fibrous ingrowth

3.  Unstable fixation


A.  Signs of osteo-integration


Take 1 year to see


1.  Spot welds

- densification of endosteal bone

- usually in the region of termination of the porous coating on the implant


THR Spot Weld


2.  Absence of any radiodense reactive lines

- may occur around the smooth portion of the implant

- this is where bone ingrowth is not expected to occur

- they should not be present adjacent to the porous coating


3.  Calcar atrophy

- this change is sometimes subtle


4.  Increased cancellous density / cortical hypertrophy distal to the coated region


B.  Failed bone ingrowth / successful stabilization by fibrous tissue ingrowth 


1. Parallel Sclerotic lines 

- remodelling signs around the porous surface 


2.  Less atrophy of the medial femoral neck


2.  No progressive migration 


3.  No local cortical hypertrophy / spot welding


C. Signs of frank implant instability 


1.  Component migration

- usually by subsidence and varus tilt


2. Progressive luceny on serial radiographs


3.  Development of inferior pedestal


THR Subsidence Uncemented Component





- slow careful insertion / make sure is advancing with each blow

- can prevent or treat with cerclage wire

- assess stability

- revert to cemented stem if unable to obtain stability with press fit


Uncemented Femur Intraoperative Fracture


Thigh pain




1.  Initial instability (lack of press fit)

2.  Failed bony ingrowth / Late instability

3.  Micromotion at distal stem

- disadvantage of proximal coating

- will usually resolve over 2 years

- only 1% severe pain

4.  Mismatch modulus of elasticity

- lower with titanium

- tend to have lower incidence of thigh pain

- smaller stems

5.  Osteoporotic bone



- can cerclage wire cortical strut grafts

- improve bony rigidity over distal stem


Stress shielding


Most common with distal press fit / fixation


THR Proximal Stress Shielding



Head size

THR Large Head





Normal feel of hip

Increased ROM




Large head

- increase volumetric wear

- less penetrative / linear  wear


Small head

- increased linear wear

- decreased volumetric wear


Livermore's studies showed

- 32mm highest volumetric wear

- 22mm highest linear wear

- determined 28 mm optimal size


High volumetric wear in metal on poly generates high levels of particles stimulating osteolysis




Head size affects dislocation because of two variables


1.  Primary arc range


Distance head can move before impinging and levering out


Increase by

A.  Increasing head:neck ratio - increases the primary arc range

B.  Tapering neck

C.  Modifying rim of cup


2.  Excursion distance


The distance the head must travel in order to dislocate once the neck begins to impinge

- jump distance

- half head diameter




Large head size does not exclude dislocation


THR Dislocated Birmingham


Methods to increase head size


Ceramic on ceramic

- size currently limited

- maximum is 36 mm alumina heads


Metal on metal

- potentially decrease wear with increased size

- due to improved fluid film and boundary lubrication


Australian Joint Registry 2010

- increased revision rates with metal on metal

- most evident with larger sizes > 32 mm

- many company's prosthesis, not just one

- especially in females and younger patients


Metal on highly cross linked poly

- increased wear resistance

- can use thinner liners

- able to use larger heads







The perpendicular distance from the centre of the femoral head to the long axis of the femur


Harris 1992

- aim for supra-physiologic offset 

- avoid making offset less than original at all costs & makes longer if possible


Soft tissue balancing equals restoring femoral offset


Effect of short offset


1.  Abductor lurch / Trendelenburg gait

2.  Increased JRF / increased wear rates

3.  Weak abduction increases O2 consumption

4.  Impingement

5.  Lax soft tiiues can cause dislocation


Decreased offset leaves the abductors lax  

- doing so means they have to act with increased force

- increases the joint reaction forces across the hip.

- rsult of this is increased wear rates


Sakalkale et al Clin Orthop 2001

- 17 patients bilateral THR

- one STD, one high offset

- liner wear 0.21mm c.f. 0.01 mm /year


Increased offset



- decreases JRF

- tightens lax abductors



- theoretical increase in torque forces on stem and cement in flexion

- cadaver studies demonstrate increased offset doesn't increase torque forces on cement & bone

- torque increased in the stem but it is below the fatigue threshold modern stems


Factors affecting offset

- neck shaft angle

- head neck length

- anteversion

- femoral osteotomy level

- position of acetabulum


How to increase offset


1. Decreasing neck shaft angle

- more varus neck shaft angle

- increases torque on implant


2. Increasing Head /  Neck length

- improves abductor tension

- worsens LLD


3.  Medialising femoral neck whilst lengthening femoral neck

- technique in high offset stems

- maintains neck shaft angle


4.  Advancing GT

- increases abductor offset


5.  Acetabular component


Lateralised liners

- increase offset whilst preserving leg length

- can worsen body weight lever arm

- do so only when increasing femoral offset insufficient


Medialising centre of rotation

- decreases offset


Checking Soft Tissue Tension and Offset


1.  Preoperative templating

- normal side

- aiming to reproduce normal biomechanics


A.  Limb length

B.  Acetabular component

C.  Femoral component


2. Intraoperative measurement


Measurement jigs

- 2 fixed reference points

- limb in consistent position

- measure length and offset

- usually pin in supra-acetabular area

- second in GT


3.  Intraoperative maneuvers


Shuck test

- distraction of hip joint with in line traction


Dropkick test

- hip extended, bend knee to 90o

- if too tight, RF is taut and passively extends the knee


Leg to leg comparison

- feel knees when legs is similar positions

- feel tension of abductors



- external rotation in extension

- flexion




AimTHR Templating


Reproduce the normal anatomical centre of rotation

Restore femoral offset 

Maintain equal leg lengths 


Usually template off normal hip




1. LLD

2. Offset

3. Femoral component

4. Acetabular component

5. Osteotomy / femoral seating




AP pelvis

- hips internally rotated 10-15o

- accounts for anteversion

- allows true neck shaft angle

- otherwise will underestimate true femoral offset


AP centred femoral head


Lateral hip joint

- used for planning location of proximal femoral opening in the piriformis fossa



- product of distance between pelvis and film

- increased in obese patients

- less in thin patients

- can use magnification marker which is know to be 10 cm


Leg Length


1.  Horizontal line through two points at inferior aspect of ischial tuberosities

- compare to lesser tuberosity


THR Minimal LLD Template


2.  Acetabular teardrop

- vertical line to centre of femoral head

- calculate difference

- multiply by 0.8 to account for 20% magnification


THR Template Severe LLD


Tear drop more reliable

- less affected by rotation

- closer to centre of rotation of hip


Note: ensure one femur is not abducted, adducted


Acetabular component


THR Template Acetabulum


Always template before femoral component

- establish centre of rotation




Establish landmarks

- line through teardrops

- ilioischial line

- superolateral margin of acetabulum



- apex just lateral to the teardrop

- medial border just lateral to ilioischial line



- 45o relative to horizontal plane

- 20o anteversion on lateral x-ray

- sufficient superolateral cover

- reproduce any uncovering intra-operatively


Mark centre of rotation


Specific cases


1. Protrusio

- template to teardrop and ilioischial line

- ream only to obtain adequate peripheral support

- calculate amount of medial bone graft


2.  Medial osteophytes / lateralised cup

- again template from teardrop / ilioischial line

- ream medially

- ensure same amount of superolateral coverage as with templating


3.  Dysplastic acetabulum

- insufficient acetabular coverage

- superolateral migration of femoral head

- restore hip centre

- calculate SL uncoverage

- if sufficient posterior wall and only uncovered anterolateral bone graft not required

- otherwise augment with femoral head / high hip centre / augmented cups


Femoral component


THR Template Femur



- template size

- calculate LLD / neck cut

- restore offset



- AP with femur internally rotated 20o

- puts true neck shaft angle in plane of film


Component size



- 2 mm cement mantle



A.  Proximal coated / metaphyseal fit

- optimal medial and lateral endosteal cortical fit of proximal femur

B.  Fully porous coated

- optimal endosteal contact in diaphyses

- 4-5cm of scratch fit


LLD / Femoral Osteotomy


Calculate LLD

- place centre of femoral component measured amount above centre rotation

- mark neck cut




If femoral head medial to centre of rotation

- offset is increased and this will decrease JRF


If femoral head lateral to centre of rotation

- offset is decreased / avoid




Trochanteric Osteotomy



1.  Standard trochanteric osteotomy

2.  Sliding trochanteric osteotomy

3.  Extended trochanteric osteotomy


Standard Trochanteric osteotomy


Standard Trochanteric OsteotomyStandard GT Osteotomy Wire Fixation



- detach GT with only abductors attached



- increasing exposure to acetabulum in difficult cases

- retensioning abductors



- difficulty fixation / unstable

- most hip surgeons now use sliding osteotomy



- detach proximal attachment of vastus lateralis

- pass retractor deep to G medius / minimus and superficial to capsule

- saw osteotomy from lateral aspect of GT angled up towards retractor

- detach any short external rotators and reflect superiorly



- 3 - 4 intraosseous wires

- claw plate


GT Osteotomy Plate Fixation


Modification / Chevron Osteotomy

- increased stability

- decreased non union



- non union

- migration

- wire breakage / painful hardware


GT Osteotomy Broken WiresGT Osteotomy Broken WireGT Osteotomy Failed Plate


Trochanteric Slide



- PA osteotomy

- vastus lateralis and G medius left attached to fragment

- fragment retracted anteriorly



- increased inherent stability

- vastus lateralis prevents proximal migration



- retractor superiorly deep to minimus and superior to capsule

- posterior elevation of vastus lateralis

- retractor under vastus lateralis insertion

- oscillating saw anterior to posterior



- wires

- grip plate


Extended Trochanteric osteotomy




Osteotomy lateral 1/3 to 1/2 of trochanter & femur

- posterior to anterior longitudinal cut

- short distal transverse cut

- levers / hinges open anteriorly

- maintains anterior vasculature / muscle attachment



1.  Aid exposure
2.  Removal cement (especially infection)
3.  Removal well fixed uncemented prosthesis
4.  Removal cement plug / bone very poor / risk of perforation high
5.  Abnormalities of the proximal femur

Contraindications / Relative

1.  Impaction bone grafting
2.  Cementing revision prosthesis


Technique ETO

- measured from tip GT
- 2 – 15 cm long

- determined from preoperative template
- need to preserve diaphysis if using distal press fit uncemented stem

- usually after implant removal
- may not be possible

- elevate vas lateralis forward
- expose linea aspera
- expose posterior femur

- use drill holes to mark osteotomy

- drill both cortices
- thin oscillating saw
- cut down through anterior and posterior femur in line with GT
- through both cortices
- transverse cut distally through 1/3 diameter
- lever open

- 3 x cerclage cables
- protect sciatic nerve / palpate / pass wires posterior to anterior
- submuscular



98 – 100% union rate by 6/12



THR Resurfacing

ConceptBirmingham Hip Resurfacing



- removal of femoral head cartilage

- resurfacing with metal

- cemented / uncemented



- standard technique


Bearing surface

- metal on metal




Relatively young man (40 - 50)



Absolute Contra-indications


Severe bone loss femoral head

Large femoral neck cyst

Small acetabulum


Relative Contra-indications



Age > 65

BMI > 35






AVN femoral head


Advantages (many theoretical)


1.  Bone preservation

- preserves femoral bone stock

- however makes acetabular preparation more difficult


2.  Improved stress transfer to proximal femur

- less proximal stress shielding

- improved proximal bone density


3.  Reduced dislocation rates

- heads 36-54 have reduced rates compared with 22-32

- can occur though if poor technique or component loosening


Dislocated Birmingham Hip ResurfacingDislocated Birmingham Resurfacing


4.  Better kinetics

- faster walking speeds

- may be better ROM

- possible better proprioception

- may be element of selection bias (i.e. is done in younger, fitter patients)


4.  Easier revision of femoral component

- better bone stock

- simply recut and use stem


6.  Possible improved longetivity

- very low wear rates metal on metal




1.  Poor modularity

- difficult to adjust LLD

- difficult to adjust offset

- patients with very abnormal abnormality better off with conventional THA


2.  Not suitable for elderly / poor bone stock

- increased risk femoral neck fracture


3.  Femoral neck fracture



4.  Metal ions

- in serum, RBC, urine



- risk metal sensitivity

- risk carcinogenesis / teratogenesis

- CI in woman of child bearing age


5.  Loosening




Femoral Neck Fracture


Incidence 0-4%

- 1.5% in a study of 3500 BHR in Australia (JBJS Br 2005)

- early in learning curve

- early in prosthesis life


Risk Factors

- decreased bone mass / osteoporosis

- elderly

- inflammatory arthritis

- females (risk x2)(AJR)

- femoral head and neck cysts

- femoral neck notching

- varus femoral component (< 130o neck shaft angle)

- cup impingement on neck

- improper implant seating

- AVN femoral Head


BHR femoral neck notchingBHR Femoral Neck Notching 2



- relatively simple

- recut neck

- femoral implant with large metal head


Revision BHR


Early loosening




Initially due to poor early manufacturing

- decreased clearance

- inadequate polar bearing

- increased peripheral bearing, seizing, cold welding and loosening


Modern machining

- small surface asperities

- improved fluid film lubrication

- polar bearing with small clearances

- very low wear and little particle production




A.  Oversized heads / notching


BHR Oversized Femoral HeadBHR Loosening


B.  Varus Femoral Component


BHR Valgus v Varus Femoral Component


C.  Femoral head AVN


Due to extensive releases required to expose / surgically dislocate femoral head


BHR Femoral Head AVN


D.  Open Acetabular Component


Theorised to cause point loading

- increased metal wear

- best to close cup


BHR Open v Closed Acetabular Component


E.  Other


BHR Acetabular Component Protrusio


Australian Joint Registry 2010


13 300 procedures


Best outcome

- male < 65 with OA

- able to get > 50 mm head size

- 3.9% 9 year


Revision rate



- 7.2% 9 years for OA


Birmingham Resurfacing

- 6.2% 9 year


Reasons for revision

- fracture 36%

- loosening 33%

- metal sensitivity 7%


Revision by diagnosis 7 years

- OA 5.8%

- DDH 14%

- AVN 6%


Revision by prosthesis

- BHR 96.5% 5 year


Revision by age 7 years

- < 55     5.6%

- 55 - 64  5.8%

- > 65     7.3%


Revision by sex 7 years

- male 4.5%

- female 9.3%


Revision by head size 7 years

- < 44mm:    13.8%

- 45 - 49mm: 8.8%

- 50 - 54mm: 3.7%

- > 55mm:     2.2%

THR Revision

A Osteolysis and Loosening

DefinitionRevision THR Osteolysis


Biological response to particulate matter

- characterised by periprosthetic osteolysis

- stimulated by wear debris

- debris gains access to any area accessible by fluid


Sources of particulate debris


1.  Wear


Mechanisms of wear

A.  Adhesion

B.  Abrasion

C.  Fatigue


Modes of wear


1.  Motion between 2 surfaces designed for motion

2.  Primary bearing surface against an non intended bearing surface

- i.e. femoral head against acetabular shell when liner has worn out

3.  Interposed third body particles i.e. bone or cement

4.  Two non bearing surfaces together i.e. back sided fretting, morse taper fretting, screws


2.  Corrosion


Electrochemical process releasing metal ions

- modular interfaces i.e. head neck

- metal on metal bearings


Types of wear particles




Cobalt alloy

Titanium alloy


Morphology of wear particles


Usually less than 1um in size


Biological response to wear particles


Small particles phagocytosed by macrophages

- unable to digest

- stimulate release of cytotoxic factors


- aggregates more macrophages

- release TNF, IL1, IL6, PGE2

- stimulated osteoclastic bone resorption


Poly wear


THR Poly WearTHR Eccentric Poly Wear


Lucent Zones


Gruen Zones


Femur:  Gruen Zones


AP 1-7

Zone 1:   Greater trochanter

Zone 4:   Tip

Zone 7:   Lesser trochanter


Lateral 8-14

Zone 8:   Anterior-superior

Zone 11: Tip

Zone 14: Posterior-superior


Charnley Zones


Acetabulum: Charnley Zones


Zone 1:  Superior 1/3

Zone 2:  Middle 1/3

Zone 3:  Inferior 1/3






1.  Easier to identify loosening in femur than acetabulum

- femur 90% accuracy

- acetabulum 65% accuracy


2.  More difficult to identify in uncemented prosthesis


3.  Lucent lines don't necessarily represent problem

- may be present in well-fixed prosthesis (retrieval studies)

- often due to remodelling 


Cemented Femur


Signs of cemented femoral component loosening

O'Neil & Harris JBJS Am'84


1.  Possible


Bone-cement lucency < 50% total

- may be due to poor cementing technique

- loosening if progressive


Cemented Femur Possible Loose


2.  Probable


Cement-implant radiolucent line >2mm wide

- progressive


Cemented Femur Probably Loose


3.  Definite


1.  Cement fracture

2.  Femoral stem fracture

3.  New lucency cement - implant interface

4.  Stem migration 


THR Probably LooseTHR Exeter Stem Fracture


A.  Subsidence

- 1-2 mm normal in first year

- > 5 mm abnormal

- measure from tip GT to head neck junction


B.  Medial midstem pivot

- pivots about midstem

- proximal medial, distal lateral

- poor cement superomedial or inferolateral


C.  Calcar pivot / bending cantilever

- distal fix strong, but proximally loose

- breakdown of proximal cement

- bone destruction


Uncemented femur


Engh classification


Types based on presence of radiolucent lines (RLL)


I.  Stable bony ingrowth


Take one year to see

A.  Spot welds at end of porous coating

B.  Absence of RLL next to porous coating

- may have RLL next to non porous coated areas

C.  Calcar atrophy secondary to stress shielding


THR Uncemented Proximal Stress ShieldingTHR Uncemented Stem Spot Weld APTHR Uncemented Stem Spot Weld Lateral


II Stable fibrous ingrowth

A.  No spot welds

B.  Parallel sclerotic lines / RLL about porous coating

C.  No migration


THR Uncemented Stem Stable sclerotic lines


III Unstable fibrous ingrowth

A.  Component migration

B.  Progressive increase RLL

- divergent RLL

C.  Pedestal formation (bony hypertrophy at tip)


THR Uncemented Subsidence


Uncemented Acetabular Component




Bone ingrowth into component averages only 12% 

- even with 84% bone contact


Non continuous radiolucent lines 

- commonly found in press fit acetabular components 

- are often not progressive


Radiographic signs of ingrowth fixation


Moore et al CORR 2006

- 3 or more 97% stable

- 2 or less, 83% unstable


Five signs

- absence of radiolucent lines

- presence of a superolateral buttress

- medial bone stress-shielding

- radial trabeculae

- inferomedial buttress


THR Uncemented Cup Superolateral Buttress 2


Radiographic signs of loosening


5 signs

- radiolucent lines that appear after two years

- progression of radiolucent lines after two years

- radiolucent lines in all three zones

- radiolucent lines 2 mm or wider in any zone

- migration > 2mm


Loose Uncemented CupLoose Uncemented Cup 2


Engh Classification


I  Osse-ointegration



B  One RLL zone 1 or 2

C  RLL zones 1 & 2


THR Uncemented Cup Stable RLL Zone 1Uncemented Cup No RLL


II Stable fibrous ingrowth

- <2mm zone 3


Uncemented Cup Stable Fibrous Ingrowth


III Unstable fibrous ingrowth

- >2mm RLL in zone 3

B Assessment Bone Loss

IndicationsRevision THR CT scan Bone Defects


1.  Loosening
2.  Infection
3.  Instability
4.  Periprosthetic fracture


1.  Exclude infection
2.  Re-establish the structural integrity & bone stock
3.  Establish normal Joint mechanics
- restore the centre of rotation of the hip
4.  Initial rigid fixation of bone graft
5.  Adequate containment of the new prosthesis


Aetiology Bone Loss

1.  Osteolysis
2.  Surgical / iatrogenic (with implant removal)
3.  Acetabular dysplasia
4.  Fracture
5.  Infection


Preoperative Assessment

1.  Exclude infection
2.  Quantify bone loss





- Paprosky




- Paprosky


Femoral Bone Loss


Paprosky Classification

I Minimal metaphyseal cancellous bone loss / intact diaphysis
- i.e. seen after removal of uncemented component without biological ingrowth on surface

II Extensive metaphyseal cancellous bone loss / intact diaphysis
- often seen after removal of cemented prosthesis


Revision THR Paprosky II FemurRevision THR Paprosky II

IIIA Metaphysis severely damaged / > 4cm diaphyseal bone for distal fixation
- grossly loose femoral component
- first generation cementing techniques


Revision THR Paprosky IIIA FemurRevision THR Paprosky IIIA 3

IIIB Metaphysis severely damaged / < 4cm diaphyseal bone for distal fixation
- cemented with cement restrictor
- uncemented with substantial distal osteolysis


Infected THR Paprosky Type IIIA

IV Extensive metaphyseal and diaphyseal bone loss / isthmus non supportive


AAOS Classification

I Segmental
- proximal (partial or complete)           
- intercalary
- greater trochanter

II Cavitary
- cancellous
- cortical
- ectasia (dilatation)

III Combined segmental and cavity

IV Malalignment
- rotational
- angular

V Femoral Stenosis

VI Femoral Discontinuity


Acetabular Bone Loss

AAOS Classification

Type I    Segmental deficiencies

Peripheral -  superior / anterior / posterior

Central - medial wall absent


Revision THR Anterior wall segmental defect

Type II    Cavitary deficiencies

Peripheral  -  superior / anterior / posterior
Central - medial wall intact


Revision THR Cavitatory Deficiency CupRevision THR Contained Defect Cup CTRevision THR Cemented Cup Anterior Wall Intact

Type III    Combined deficiencies

Type IV     Pelvic discontinuity


Separation of anterior and posterior columns

Type V    Arthrodesis


Paprosky Classification

Based on ability of the remaining host bone

- to provide initial stability to a hemispherical cementless acetabular component

- until ingrowth occurs

Type 1    


Undistorted rim
- anterior and posterior columns intact
- no superior migration

- may have some contained deformities
- ishium, teardrop and Kohlers line intact

Type 2


Distorted but intact rim
- can support a hemispherical cementless implant


Revision THR Paprosky Type 2 Cup


Some distortion, minimal superior migration
- at least 50% good support by host bone
- anterior and posterior columns intact
- no substantial osteolysis of ischium or teardrop



- superomedial migration but superior rim intact


Revision Acetabulum Paprosky Type IIA



- < 1/3 superior deficit

- remainder is still supportive

- replace with allograft for bone stock



- medial migration to Kohlers, but wall intact

- rim is supportive

- manage as for protrusio


Revision Acetabulum Paprosky Type IICRevision THR Superior Migration Cup but Rim intact

Type 3


Non supportive rim
- columns not supportive, superior migration> 3 cm

- require structural allograft for support


Revision THR Type 3 Acetabulum

4 radiographic criteria

1.  Superior migration of the hip centre
- indicates damage to anterior and posterior columns
- supero-medial indicates greater damage to anterior column
- supero-lateral indicates greater damage to posterior column

2.  Ischial osteolysis
- bone loss inferior posterior column

3.  Teardrop osteolysis
- inferior anterior column and medial wall

4.  Position of the implant relative to Kohler’s line
- deficiency of anterior column



-  > 40% host bone contact

-  < 50% rim missing



- < 40% host bone contact

- > 50% rim missing



C Approach and Implant Removal

Pre-operative Planning

CT / quantify bone loss
X match 4 units
Cell saver
Anaesthetic review
Bone graft (cortical, cancellous)
Component removal gear

- extraction gear for femur / liners

- cement removers for cemented femur

- curved osteotomes for cemented cup

- X-plant for uncemented cup
Revision long stem femoral implants
Revision acetabular implants including cages



Posterior approach
- often easiest in revision
- good for ETO


Recreate fascial and muscular layers

- aids exposure and closure

Wide exposure of hip joint
- removal of all pseudocapsule
- expose entire proximal femur & acetabulum


Extended Trochanteric osteotomy




Osteotomy lateral 1/3 to 1/2 of trochanter / femur

- posterior to anterior longitudinal cut

- short distal transverse cut

- levers / hinges open anteriorly

- maintains anterior vasculature / muscle attachment



1.  Aid exposure
2.  Removal cement (especially infection)
3.  Removal well fixed uncemented prosthesis
4.  Removal cement plug / bone very poor / risk of perforation high
5.  Abnormalities of the proximal femur

Contraindications / Relative

1.  Impaction bone grafting
2.  Cementing revision prosthesis


Technique ETO

- measured from tip GT
- 2 – 15 cm long
- need to preserve diaphysis if using distal press fit uncemented stem

- usually after implant removal
- may not be possible

- elevate vas lateralis forward
- expose linea aspera
- expose posterior femur

- use drill holes to mark osteotomy

- drill both cortices
- thin oscillating saw
- cut down through anterior and posterior femur in line with GT
- through both cortices
- transverse cut distally through 1/3 diameter
- lever open

- 3 x cerclage cables, tension
- protect sciatic nerve
- submuscular



98 – 100% union rate by 6/12


Removal Femoral Implant

A.  Cemented



- must clear shoulder of prosthesis
- must ensure no GT overhang or will fracture on removal

Extraction devices
- stem often easily removed if cemented
- extraction devices hook around proximal prosthesis & backslap
- can release cement – implant interface
- combination flexible osteotomes, micro sagittal saw, small burr

Cement removal
- aided by ETO
- use arthroscopy light down femur

Cement removal kit
- flexible osteotomes, reverse hooks, cement splitters
- split cement radially & then removed
- can use high-speed burr
- may require distal window

Removal of cement plug
- remove proximal cement
- drill guide in centraliser
- insert tap, then extract


Need to be very careful to avoid inadvertant perforation

B.  Uncemented

Can be very difficult to remove a well fixed stem

- i.e. if removing for infection

Consider component design
- proximally coated
- extensively coated

Breakdown osseointegration
- flexible osteotomes
- sagittal saw
- very difficult
- can perform ETO about stem

Extraction devices

- company specific

- hook under neck


Broken Stems
- stem is invariably well fixed distally
- osteotomy to site of fracture
- +/- distal window

Acetabulum Removal


Acetabular revision only

1.  Leave femoral component in situ



- femur not loose / damaged / good orientation

- need to be able to match new cup / poly to femoral head


- can remove head if modular (use company device to lever off)
- make anterior pocket for femoral stem

- protect trunion with swab



- can be a problem putting a ceramic head on an old trunion

- if needed, can get a ceramic head with a metal liner for trunion

2. Removal of cemented Femoral component / Re-cement a smaller prosthesis into a well fixed cement mantle


Revision Cup Only Cement in Cement Femur PreRevision Cup Only Cement in Cement Femur Post

- as above


Re-cement prosthesis

- ensure cement mantle clean and dry

- trial small component

- cement in cement revison with high viscosity cement

- insert cement when very viscous

- put in new prosthesis very early


Removal Cemented Acetabulum

1.  General principle is to loosen poly cup from cement
- do so with curved gouges
- between cement & cup
- cement then removed piecemeal

2.  Can simply ream out the poly

3.  Insert threaded extractor through drill hole in poly
- then disimpact poly from cement


Uncemented Acetabulum

- may just be changing liner and leaving cup
- may need to remove well fixed cup i.e. infection

- may be removing loose cup


1.  Company specific removal instruments
- need to disengage locking mechanism

2.  Simply lever out liner with osteotomes

3. Drill hole in liner 4.5 mm
- insert 6.5 mm screw to push liner out

Metal Shell

1.  Curved osteotomes
- risk bone loss

2.  Zimmer Explant Acetabular Removal System
- 3 sizes depending on implant size
- central head to sit in liner
- must remove screws first, then replace liner
- diamond blades cut between cup and bone
- initial blade short
- second is thin and full radius

Intrapelvic acetabulum / cement


Intrapelvic Cement



Can be life threatening if just pulled out from standard approach


Preoperative contrast studies

General surgeon / vascular surgeon available



A.  No aneurysm
- lateral window of ilioinguinal
- elevate iliacus subperiosteally from table of ilium
- remove under direct vision

B.  False aneurysm
- Rutherford Morison approach
- general / vascular surgeon



D Reimplantation Acetabulum

Principles of Acetabular reconstructionRevision Acetabulum Post Paprosky Type IIIC


Restore centre of rotation
Restore acetabular integrity
Component containment
Secure fixation

Preoperatively planning

Know components in situ (esp if leaving femur)
Quantify and grade bone defects
Beware intrapelvic cement / cup (angiogram)


Basic Guidelines


> 50% host bone contact

- use press fit uncemented cup augmented with screws


< 50% host bone contact

- use metal augment in elderly to reconstruct defect

- use allograft augment in young to reconstruct defect

- press fit cup if able

- otherwise must use cage

Paprosky Type I, II A and B


I Rim intact

II A Mild superior migration / superior rim intact

II B < 30% superior rim missing

1.  Uncemented Jumbo rim fit cup

- > 50% host bone available for ingrowth
- > 2/3 rim intact

- implant in usual position
- preferentially ream anteriorly
- preserve posterior column
- some uncovering superiorly allowed
- usually augment with screws
- +/- postoperatively NWB 6/52

- 12-15 year survival between 81-96%


Revison THR Type I AcetabulumRevision THR Jumbo Cup 2


2.  Impaction Bone Graft +/- Mesh + Cemented Cup


Revision Acetabulum Type IIIBRevision Acetabulum Type IIB Superior Mesh and Impaction Bone Graft


Type IIC


Type IIC: Medial wall deficiency but intact


A.  Particulate graft medially, jumbo cup


Revision THR Type IIC AcetabulumRevision THR IIC Jumbo Cup + medial bone graft


B. Impaction bone graft, cemented cup


Revision Acetabulum Type IICRevision Acetabulum Type IIC Impaction Bone Grafting


C.  Cement +++


Indicated in elderly patients


Revision Acetabulum Type IIcRevision Acetabulum Cement +++


Segmental Medial Wall deficiency

A.  Allograft + Antiprotrusio Cages + Cemented Cup


- Ganz / Muller / Burch Schneider

- variations on them

- hook or screws into ilium

- hook or screws onto ischium

- can have extension for screws onto pubis


Revision THR Burch Schneider Cage

B.  Mesh + Impaction Bone grafting


Type IIIA defects



- Rim < 50% missing, > 40% host bone contact

- want to reconstruct defect but don't need cage


1.  Uncemented rim fit cup / screws / Structural bone graft

- defect superolateral rim < 50% to support cup
- > 50% host bone contact

- allograft will not grow onto uncemented cup

- allograft to reconstuct defect

- femoral head allograft reconstruction (no 7 shape)
- fix with 6.5 mm screws
- tap first to prevent fracture
- ream into bone

2.  Impaction bone graft +/- mesh + cemented cup

Revision THR Type IIC AcetabulumRevision THR Impaction Bone Graft Acetabulum



1.  If required, convert uncontained defect into contained defect
- use titanium mesh fixed with screws
- acetabular rim or medial wall mesh (Stryker)


Revision THR Type IIIC Acetabulum Mesh Impaction Bone GraftRevision THR Type IIIA Acetabulum Pre IBG

2.  Impact morcellised cancellous bone graft
- tamps or reverse reaming
- progressively smaller impactors
- need 5 mm of bone graft

3.  Insert prosthesis / Cemented poly liner


- 85% 12 year survival
- 80% 15 year survival

Important Points

1.  Rigorous technique important

2.  Fresh frozen allograft
- does this perform better than irradiated BG

3.  TWB 6 – 12/52


3.  Trabecular metal components

New material made of element tantalum

1.  Interconnecting porous material
- 80% porous
- allows 2-3 X bony ingrowth

2.  Less stiff
- improved remodelling of BG underneath

3.  High cancellous bone coefficient of friction
- excellent initial stability
- may need less than traditional 50% host bone contact
- may not need screws

Ream host bone for press fit cut
- trial then secure trabecular augment with screws
- press fit cup with cement between augment and cup
- screw augmentation of cup

4.  Bilobed uncemented acetabular components


Bilobed Revision Cup

- superolateral deficiency
- revision
- DDH cups

- can be difficult to get version right




- < 50% rim intact, < 40% contact

- must reconstruct for stability

- unable to use uncemented component

- use bone graft to reconstruct

- need cage for stability


1.  Structural Allograft + Cage


Revision Acetabulum Bulk Structural Allograft + Cage

- when inadequate bone stock precludes the use of uncemented acetabular components

- cannot implant onto allograft
- graft under the cage
- secure with cage
- cement poly into it

- allograft reconstruction of rim with femoral head
- allograft particulate material in base
- secure cage to posterior column ilium and ischium
- 3 screws in each
- cement all poly cup into cage

- 75% 10 – 15 year survival

Option:  Custom-made triflange components

CT guided model of pelvis
- custom made acetabular cage
- fits defect exactly
- flanges perfectly designed and not malleable to improve strength
- HA coated
- cement poly cup into it

- massive defects

- 90% 4.5 year survival in complicated patients


2.  Impaction Bone Graft +/- Mesh + Cage + Cemented cup


Revision THR Type 3B AcetabulumRevision THR Acetabular Mesh Bone Graft Cage


Pelvic discontinuity


Revision THR Pelvic Discontinuity0001Revision THR Pelvic Discontinuity 2Revision THR Pelvic Discontinuity 3

1.  Plate and bone graft posterior column


Revision THR Plate Posterior ColumnRevision THR Plate Posterior Column Lateral

2.  Plate + Cage reconstruction


3.  Cup Cage Reconstruction



- large tantalam cup inserted for reconstitution of discontinuity

- bone graft inserted

- cage, cement in cup


Revision THR Cup Cage0001Revision THR Cup Cage0002Revision THR Cup Cage0003


E Reimplantation Femur

Implant Options


1.  Long stem cemented revision femoral stem


Modern cementing techniques
- removal of neocortex

- use in all cases
- good with elderly fragile bone
- can use Abx cement (decreases infection rate)

- Paprosky Types I – IV
- very versatile



- complete removal / debridement of neocortex

- modern cementing techniques

Howie JBJS Br 2007
- 219 patients, 9 year follow up
- collarless double taper
- 98% 10 year survival

- ? increased non union with ETO


2.  Extensively porous coated diaphyseal fitting uncemented stem

- Paprosky Types I, II, IIIA

- 90- 95% 10 year survival

- fracture
- stress shielding with additional proximal bone loss

3.  Modular diaphyseal fitting, proximal filling uncemented stem


Revision THR Modular Long Stem UncementedModular Revision Implants

- press fit metaphyseal segment
- slotted diaphyseal segment
- initial stability through distal fixation

- Paprosky Types I – IIIB

Smith J Athroplasty 1997
- nil revisions at 5 years
- 7% radiographically loose

Type 3 Revision Femur 2


4.  Impaction bone grafting

- morcellised bone graft is osteoconductive, not osteoinduction
- resorption and eventual replacement new bone
- 6 – 12 months
- process is incomplete

Van der Donk Clin Orthop 2002
- 30% complete 6/12

- 90% complete 12/12


1.  Particulate cancellous autograft 7-10 mm
2.  Contained defect
3.  Ability to convert uncontained into contained (i.e. mesh)

- technically demanding
- takes time
- need axial and rotational stability
- avoid stem subsidence > 5 mm

1. Uncemented distal fixation not possible (< 4cm diaphysis)
2. When reconstruction of proximal bone stock important
- young patient in whom biological solution more desirable


- choose stem 2 cortical diameters longer than most distal lytic area

- full exposure of proximal femur
- removal stem & cement


Can leave distal plug
- not infected
- > 2 cm past planned tip location

Create contained defect
- reconstitute femoral tube
- create contained defect
- wire mesh & cerclage wire
- prophylactically cerclage wire shaft if diaphysis flimsy

Distal Occlusion
- threaded intramedullary plug inserted on guide rod
- impacters tested to see max depth of insertion before abutment on canal
- morsellised allograft inserted
- impactor & slap hammer slid over guide wire
- graft impacted to predetermined depth
- continued by introducing more chips with larger impacters
- stopped when level is 10 cm from tip of GT

Proximal Impaction
- appropriate proximal impactor equivalent to selected stem used
- used to force chips against walls of canal
- then larger distal impactor used
- alternated till canal filled
- should be firm neo-canal

Trial Reduction
- trial stem inserted
- depth of insertion marked
- proximal impactor driven in another 5 mm
- creates room for cement

- cemented polished collarless double tapered stem

- NWB for ? 3/52
- then gradual inc over next 3/ 12


Halliday JBJS Br 2003
- 90.5% 10 year survival

Elting Clin Orthop 1995
- 93% graft incorporation
- stem subsidence in 48%

Elridge JBJS Br 1996
- > 5 mm subsidence in 22%


Management Plan

Assess Metaphyseal & Diaphyseal Bone Stock

Grade Paprosky, then manage appropriately

Paprosky Type 1



Minimal metaphyseal cancellous bone loss
Intact diaphysis     



Simple revision
- can use standard or any revision stems

A. Uncemented
- standard length proximal fit and fill
- need appropriate initial stability

B. Cemented standard length stem
- must remove neocortex
- need good cement interdigitation

Izquierdo JBJS Br 1994
- 90.5% 19 year survival


Revision Femur Type 1 Standard Cemented Stem Pre opRevision Femur Type 1 Standard Cemented Stem Post op

C. Cement onto old mantle
- clean and dry mantle critical
- thin layer of blood 85% reduction shear strength

Lieberman et al JBJS Br 1993
- 19 cases
- no loosening at 5 years in all


Revision Femur Paprosky 1 Revision Femur Paprosky 1 Cement in old Cement Mantle


Type 2



Extensive metaphyseal cancellous bone loss
Diaphysis intact



A.  Extensively porous coated diaphyseal fitting implant

Paprosky 90& osteointegrated


Calcar Replacement Uncemented Stem

B.  Long stem cemented revision stem


Revision Femur Long Stem Cemented Femoral Component

C.  Modular diaphyseal fitting, metaphyseal filling uncemented prosthesis

D.  Impaction bone grafting


Type 3A



Metaphysis non supportive
> 4 cm diaphysis proximal to isthmus


Type 3 A FemurType 3A Femur Lateral

A.  Extensively porous coated diaphyseal fitting implant


Type 3 Revision Femur

Paprosky 20/22 91% osseointegrated

B.  Long stem cemented revision stem


Revision Femur Long stem Cemented Component

C.  Modular uncemented


D.  Impaction bone grafting


Revision Femur Type IIIA Pre Impaction Bone GraftingRevision Femur Type IIIA Post Mesh and Impaction Bone Grafting


Type 3B



Metaphysis non supportive
< 4cm diaphysis proximal to isthmus



A.  Extensively coated diaphyseal fitting

Paprosky 4/8 failed

- i.e. need > 4cm of diaphysis for this to work

B.  Long stem cemented revision stem

C.  Modular uncemented, stem with flutes for rotational stability

D.  Impaction bone grafting


Revision Femur Type 3 Mesh and Impaction Bone Grafting


Type 4



Metaphysis and diaphysis extensively damaged
Isthmus non supportive



A.  Long stem cemented revision stem

B.  Impaction bone grafting


Management Bone Defects


1.  Segmental defects

A.  Must bypass any cortical defect by two cortical diameters to reduce fracture risk

B.  Cortical Strut onlay grafts

2.  Extensive proximal bone loss


A.  Calcar replacing


Calcar Replacing THRCalcar Replacing Hip Replacement

- proximal segmental defect < 3cm

McLaughlin JBJS Am 1996
- 38 hips 11 years
- 80% survival
- another 10% radiologically loose
- 20% dislocation rate


B.  Napkin ring  / Calcar graft Allograft

- circumferential proximal defects < 3cm

- poor
- 40-60% resorption


C.  Proximal Femoral Replacement / Tumour prosthesis

Results disappointing
- however design may be improving

Malkani JBJS Br 1995
- 33 hips 11 years
- poor function (50% severe limp or unable to walk)
- 64% 12 years survival
- 22% dislocation


D.  Bulk Structural Proximal Femoral Allograft

- proximal defect > 3 cm

- desired stem cemented into allograft
- press fit distally into host femur
- step cut graft host junction
- secure cerclage wire and onlay cortical strut
- proximal host bone wrapped around allograft with ABD preservation

- very important – abductor mechanism must be secured and protected

Gross 1998
- 200 patients, 5 years follow up
- 12.5% revision
- revised for infection, dislocation, graft-host non union


Transient Osteoporosis Hip



Self limiting syndrome of unknown aetiology

- hip pain associated with osteoporosis of proximal femur 





- AVN of the hip in pregnancy is rare but possible

- TOH tends to be diffuse on MRI, while AVN is localised

- extends to neck and metaphysis

- transient osteoporosis has normal bone scan





- M: F 3:1


Two Groups

1. Men 40-50 years old

2. Women usually 3rd trimester of pregnancy




Unknown / Theories

- ischaemia


- virus / toxin


Only predisposing factor is pregnancy




Biopsy shows many features in common with AVN, but it is non-specific

- edematous fluid & marrow

- inflammation

- fat necrosis

- reactive bone formation

- widely spaced trabeculae


Clinical Features


Acute onset

- AVN tends to be insidious


Mechanical hip pain

- usually FROM


Rarely sub-capital fracture results


Natural History


Three distinct temporal phases


1. Initial 

- sudden onset severe pain

- disability >> signs

- lasts 1/12


2. Plateau

- symptoms stabilise

- osteopenia seen on xray

- lasts 2/12


3. Regression

- lasts 3/12




Shows diffuse osteopenia of entire proximal femur 

- 1/12 after onset

- may have "Phantom" appearance of proximal femur 

- rarely the pelvis can be affected too




Key is that with TOH the MRI changes are diffusely affecting the proximal femur

- AVN it is localized to a portion of the head


Marrow oedema

- TI decreased SI 

- T2 increased SI due to oedema







Osteoporosis 2° joint disease

Metabolic cause osteopenia

Permeative - neoplasia 








Self limiting condition

- rapidly improves after delivery


Need to prevent fracture

- protected weight bearing in pregnancy





- simultaneous pinning & LSCS


Non pregnancy




Varenna et al Bone 2002

- 16 cases treated with IV pamidronate

- resolution of symptoms and normalisation of MRI findings




Trochanteric Bursitis & Gluteus Medius

Trochanteric Bursitis




Repetitive friction of iliotibial tract over GT




Overuse in athletes

Common post THR


May be associated with gluteus medius tears




Pain over upper lateral thigh with activity

- often related to hip flexion




Localised tenderness & swelling over & posterior to GT


Pain with resisted abduction




Tears in gluteus medius

Stress fractures

Iliopsoas tendonitis

Intra-articular hip pathology

Spinal pathology





May demonstrate fluid in bursa


Non operative Management


HCLA injection

- virtually all respond to HCLA but may need several

- almost never need surgery


Operative Management




Baker et al Arthroscopy 2007

- arthroscopic resection bursa in 30 patients

- successful in all but one who went on to have a successful open bursectomy


Bursectomy + ITB lengthening


Craig et al ANZ J Surg 2007

- open proximal Z lengthening ITB in 17 patients

- one poor result

- one patient had a secondary repair gluteus minimus with excellent result


Distal ITB lengthening


Pretell Int Orthop 2009

- distal lengthening in 13 patients average age 50

- 12/13 good results

- 1 post op seroma


Tears Gluteus Medius and Minimus




Sporting injuries










Non operative Management


Rest / physio

- stretching +++

- eccentric exercises

- correction of LLD with shoe lift








Operative Management




Repair of tears + bursectomy

- open or arthroscopic




Voos et al Am J Sports Med 2009

- arthroscopic repair tendon tears in 10 patients

- all had complete resolution of symptoms


Lequesne Joint Bone Spine 2008

- open repair in 8 patients

- lateral tears of gluteus medius all seen on MRI

- 3 gluteus medius tears were not seen on MRI

- good results in 7/8 patients