PatelloFemoral Joint

Acute Patella Dislocation

Acute Patella DislocationPatella Dislocation Skyline

 

Mechanism

 

1. Direct lateral blow to patella

- usually with knee partly flexed and quadriceps relaxed

 

2.  Indirect low energy injury

 

Epidemiology

 

2 Groups of Patients

 

1.  Patients with no predisposition to patella instability

- traumatic injury

- contact sports

 

2.  Patients with anatomic predisposition to instability

- atraumatic / minimally traumatic injury

- young / valgus malalignment / ligamentous laxity / malrotation

 

Associated injuries 

 

Osteochondral fracture (40-50%)

- LFC or medial facet patella

- patient will have haemarthrosis

- must identify this group, investigate and manage appropriately

 

Pathology

 

Medial Patellofemoral Ligament (MPFL)

- from MFC between femoral epicondyle and adductor tubercle

- to superolateral border patella

- deep to retinaculum / superficial to capsule

 

Usually tears off femur

 

Acts as a checkrein to lateral patella subluxation

- will usually be torn in all patients with patella dislocation

 

Recurrence rate

 

15-20%

- more likely in those predisposed to instability

 

Reduction technique

 

Conscious sedation

- knee extended

- medial force on patella

- usually reduces easily

- splint

 

Examination

 

Haemarthrosis post reduction

- investigate further

 

Xray

 

AP / Lateral / Skyline

- examine carefully for loose body

 

Knee Xray Loose Body

 

CT

 

Shows loose body and origin

 

MRI

 

Demonstrates

- MPFL tear

- cartilage damage

- loose body

 

Patella Dislocation Chondral Damage Medial Facet PatellaPatella Dislocation MRI MPFL Disruption Patella SidePatella Dislocation MRI Loose Body Notch

 

Knee Loose Body PFJPatella DIslocation MRI OCD LFC MPFL Patella Chondral Damage

 

Management

 

Non operative

 

Options

 

1.  First time dislocator with no associated injury

- splint in full extension with lateral patella pad

- reapproximate torn medial structures

- 4 weeks

- then begin VMO exercises +++

 

2.  Recurrent dislocator

- splint only initially for symptom relief

- early ROM and rehabilitation

- no role for long term splintage

 

Operative

 

Indications

- loose body

- management of OCD Lesions

- +/- early MPFL repair

 

Arthroscopy

 

Assess Patella and Femoral Lesions

 

1.  Small pieces cartilage

- remove loose bodies

- microfracture if necessary

 

Patella Dislocation Loose BodyPatella Small Chondral Lesion

 

2.  Large Osteochondral Fragment

- usually medial patella or lateral femur

- open approach to knee

- reduce and fix with bioabsorbable compression screws / pins

 

3.  Large Chondral piece with minimal or no bone

- can attempt suture fixation

- need to warn of risk of failure and need for reoperation

- careful monitoring

 

4.  Large irreparable chondral lesion

- remove loose body

- microfracture / abrasion initially

- if continue to be asymptomatic, consider alternative procedure

- MACI / mosaicplasty

 

Patella Dislocation Unsalvageable Chondral LesionPatella Dislocation Removal Medial Facet Cartilage

 

Early MPFL repair

 

Patella Dislocation MPFL Disruption Patella Arthroscopy

 

Issue

- ? would recurrence rates be reduced with early repair / reconstruction MPFL

 

Results

 

Palmu et al JBJS Am 2008

- RCT of early operative treatment in adolescents < 16

- very high rates of recurrence in both groups (70%)

- up to 50% of this group had contralateral patella problems

 

Silanpaa et al Am J Sports Med 2008

- compared operative and non operative treatment

- all operative patients had arthroscopic repair of medial retinaculum

- equal (20%) redislocation in each group

 

Christiansen et al Arthroscopy 2008

- RCT comparing non operative to open MPFL femoral repair

- redislocation rates the same in each group

 

Camanho et al Arthroscopy 2009

- RCT of operative v non operative

- excluded patients with flat trochlea / valgus > 15o / patella alta

- in surgical group determined if injury on patella side or femoral side

- 7 from patella repaired arthroscopically

- 10 from femur repaired open with anchors

- 0/17 in surgical group redislocated

- 8/16 in surgical group redislocated

 

Problem

 

1.  Can repair MPFL but if anatomically predisposed to instability

- will still redislocate and rerupture MPFL

- exclude valgus / alta / flat patella

 

2.  If attempting early repair, need to address specific MPFL pathology

 

Open Technique

 

Very important to determine if torn from patella or medial epicondyle

- MRI very useful

 

Medical epicondyle avulsion

- over medial epicondyle

- divide deep fascia

- elevate VMO

- identify MPFL

- repair using bone anchors

 

MPFL repair medial epicondyle

 

Arthroscopic technique

 

Pass spinal needle medial to patella

- insert 1 PDS

- retrieve laterally with loop retriever

- repeat multiple times

- mini - incision and tie from outside in

 

 

 

Bipartite Patella

Ossification

 

Patella may develop from one or multiple ossification centres at 3 years

 

Failure of centres to fuse may produce bipartite or tripartite patella

- usually bilateral and painless

 

Classically superolateral

 

Classification Saupe

 

I   Inferior Pole 5%

II  Lateral 20%

III Superolateral 75%

 

Bipartite patella SuperolateralBipartite patella

 

CT

 

Bipartite Patella CT

 

Clinical

 

1.  Overuse

- pain may result from repetitive microtrauma 

- injury to synchondrosis

- point tender & swollen

 

2. Acute injury

- can get acute injury with minor separation

- reports of bipartite patella healing post injury

- check SLR to ensure quadriceps tendon intact

 

Investigation

 

MRI

- confirms quadriceps tendon intact

- look for increased uptake ? symptomatic

 

Bipartite patella MRI

 

Bone scan

- shown to have increased uptake in symptomatic / asymptomatic knees

 

Management 

 

Non operative Management

 

Majority will settle with non operative management

- mmobilisation for 4 weeks

- avoid impact sports

 

Ultrasound / Exogen

- reports of healing bipartite patella post injury

 

Operative Management

 

Options

 

Lateral release

 

Adachi et al Arthroscopy 2002

- lateral release performed

- excellent results in 13 and good in 4

- nearly 2/3 healed and remainder partially healed

- bone union more likely in patients < 15

 

Mori et al Am J Sports Med 1995

- 15/16 united at 8 months post lateral release

 

Removal of bipartite patella

A. Open

- easiest

- often need to reattach quadriceps tendon with anchors

 

B. Arthroscopic

 

Bipartite PatellaBipartite Patella

Chondromalacia Patellae

Definition

 

Patella Chondromalacia

 

Softening and fibrillation of articular cartilage of patella

 

Problem

- softening and fibrillation often seen in asymptomatic population

- can have typical anterior knee pain without retro-patellar changes

 

Epidemiology

 

Female adolescent

- recent increase in activity

 

Query on continuum to OA

May be a separate pathology

 

Aetiology

 

Unknown / varied

 

Mechanical

 

Acute

- direct trauma

- PFJ dislocation

 

Chronic

- PFJ instability

- LPPS (lat patellar pressure syndrome)

- quadriceps imbalance

- VMO weakness

 

Biological

 

Idiopathically abnormal cartilage unable to tolerate load

- inflammatory arthritis

- recurrent haemarthrosis

- sepsis

 

Iatrogenic

- repeated intra-articular steroids

- prolonged immobilisation

 

Degenerative

- primary OA

 

Pathology

 

Basal degeneration of cartilage at deep level

- pain due to nerve endings in subchondral bone being stimulated by variations in pressure

 

Different to pathology of OA

-"Basal Degeneration" compared with surface 

 

Classification

 

Grade 1 

- localised softening with no break in surface

 

Grade 2 

- fibrillation or fissured

 

Patella Fibrillation ArthroscopyPatella Grade 2 Chondromalaciae

 

Grade 3 

- fissuring to bone

- crab meat appearance

 

Patella Grade 3 ArthroscopyChondromalacia Patella Grade 3

 

Grade 4 

- bone exposed / full thickness chondral defect

 

Patella Grade 4 Arthroscopy

 

Symptoms

 

Non-specific

- dull aching discomfort anterior knee

- cinema sign / sitting flexed generates pain

- stairs

- catch & pseudo-locking

- swelling

 

Signs

 

PFJ crepitus

- seen in 60% asymptomatic teens

 

Exclude malalignment

 

Xray

 

Exclude malalignment

 

Management

 

Non-operative

 

NSAIDS

Quadriceps exercises

Activity modification

Cut out brace & taping

Hyaluronic acid injections

 

Operative

 

Options

 

Patellar Shaving

 

Federico et al Am J Sports Med 1997

- arthroscopic shaving in 36 patients with grade 2 or worse

- no malalignment

- all had some improvement

- only 50% good or excellent result

 

Full thickness chondral defect

 

Local Excision & Subchondral Drilling / Abrasion

 

Lateral Release

 

MACI

 

Gobi et al Am J Sports Med 2009

- chondral lesions on patella and trochlea

- all had reasonable symptomatic results

- tended to decline over time in patella and with multiple lesion

 

 

 

 

DDx Anterior Knee Pain

Plica 

 

Jumper's knee / Tendonitis

 

Bursitis

- prepatellar most common

- Pes anserinus 

 

Excessive Lateral Pressure Syndrome / Patella Tilt

 

Hoffa's Disease / Fat Pad Syndrome

 

ITB Syndrome

 

RSD

 

Others

- RA

- Synovial Chondromatosis

- Meniscal tears

- PVNS

- PF Arthritis

- Tumours - hemangiomas 

- Referred Pain - hip / back /ankle

- Cruciate ligament insufficiency / reconstruction

 

Adolescent Knee Pain

 

Bipartite / Multipartite Patella 

 

Sinding Larsen Johannsen

  

Maltracking /alignment 

- ELPL / alta / baja 

 

Osgood-Schlatter's

- local inflammatory around avulsions of apophysis

- self -limiting

- rarely requires surgical management

 

Menelaus-Batten Syndrome

- Johannson- Larsen's disease that affects upper pole patella

- may see fragmentation

 

Hypermobile patella

- ligamentous laxity

 

 

Fat Pad Syndrome

Definition

 

Hoffa's syndrome

- impingement of the fat pad with knee ROM

 

Epidemiology

 

Rare

Diagnosis of exclusion

 

Theory

 

May be more prevalent in patients with intact ligamentum mucosum

 

Diagnosis

 

Hoffa's sign

- apply pressure to fat pad each side of patella tendon with knee in flexion

- extend knee

- will cause impingement

 

HCLA

- behind patella tendon into fat pad

- will relieve pain

 

MRI

 

See increased signal in fat pad

 

Fat Pad Impingement MRIFat Pad Impingement 2

 

 

PFJ OA

EpidemiologyPatella OA Medial Facet

 

1 in 10 patients with symptomatic knees have isolated PFJ OA

 

Aetiology

 

Obesity

Repetitive deep flexion

Malalignment

Lateral patella tightness

Blunt trauma

 

Symptoms

 

Anterior knee pain

- rising from chair

- ascending stairs

 

DDx

 

Plica

Tendonitis

Patella tilt

 

Signs

 

Tender patella

- especially lateral facet

 

Pain with movement PFJ

 

X-ray

 

Laurin View

- assess tilt

 

Patella OA Tilt

 

Merchant view

- assess subluxation

 

Patella OA Subluxation

 

Lateral

 

Patella OA Lateral

 

Arthroscopy

 

PFJ OA ArthroscopyPFJ OA Arthroscopy

 

Patella Grade 4 ArthroscopyPatella Trochela Grade 4 Damage

 

Management

 

Non Operative

 

Medications

- NSAIDS

- glucosamine

 

Cut out braces

 

Exercises 

- hydrotherapy

 

Operative

 

1.  Lateral release

 

Indications

- lateral tilt

- lateral facet OA

- lateral retinacular tightness

- limited goals

 

Patella Tilt Moderate OAPatella Tilt Moderate OA MRI

 

Lateral release

 

Results

 

Aderinto et al Arthroscopy 2002

- retrospective study of 49 patients

- 80% patients felt some reduction in pain

- at 2 - 3 year follow up, 33% very satisfied and 26% satisfied

- 41% unsatisfied

 

2.  TTT

 

A.  Anterior transfer of TT

 

Maquet procedure

 

Elevation of TTT with insertion bone graft

- originally described elevating by 2.5 cm

- problems with skin necrosis / prominence TT / tendonitis

- reduced to only 1 cm and recommended via an anterolateral incision

 

Maquet APMaquet Lateral

 

Results

 

Largely discarded

- causes superior patella tilt

 

Schmid Clin Orthop Related Research 1993

- 35 knees

- 80% good, remainder fair or poor

 

B.  Anteromedial transfer of TT

 

Fulkerson

 

Oblique osteotomy 45˚

- enables antero-medial transfer of tibial tuberosity

- unloads the PFJ and the lateral facet simultaneously

 

Fulkerson Osteotomy APFulkerson Osteotomy Lateral

 

Results

 

Fulkerson et al Am J Sports Med 1990

- 93% good or excellent results in 30 patients at 2 years

- 75% good in 12 patients at 5 years, no excellent

 

3.  Facetectomy

 

Indication

- previous fracture

- isolated OA to one facet

 

Options

- open

- arthroscopic

 

Open procedure

 

Midline incision

- open retinaculum medial or lateral

- excise medial or lateral facet

- leave central ridge to ensure tracking

 

Patella Medial OA post FracturePatella Medial Facet OA Post Fracture Arthroscopy

 

Results

 

Paulos et al Arthroscopy 2008

- arthroscopic lateral release and partial lateral facetectomy

- 80% very satisfied or satisfied

 

4.  Patellectomy

 

Problem

- doesn't completely relieve pain (leaves trochlea)

- extensor weakness and lag / problems with stair descent

 

Technique

- open retinaculum

- excise patella in full

- close retinaculum tightly

- VMO advancement

- this increases strength and decreases lag

 

Patellectomy LateralPatellectomy Skyline

 

5.  PFJR

 

Predates TKR by 10 years

 

Indications

 

Good results in 

- OA from trauma without malalignment

 

Poorer results in OA from unknown cause

- risk developing femoro-tibial OA

- need revision

 

Patient

- isolated PJF OA

- < 60 years old

 

Contra-indications

 

Inflammatory conditions

Patella maltracking and malalignment

Tibiofemoral arthritis / medial or lateral joint pain

 

Malalignment

 

Correct large Q angles preop with TTT

- some correction of maltracking can be obtained intra-op via component positioning and lateral release

 

Failures

 

PF instability

Progressive tibio-femoral degeneration

Loosening rare (< 1%)

 

Types

 

Avon (Stryker)

LCS (Depuy)

 

Results

 

Odumenya et al JBJS Br 2010

- 5 year follow up of 50 patients

- no revisions

 

Ackroyd et al JBJS Br 2007

- 109 patients followed up for 5 years

- survival rate 96%

- 80% good outcomes

- 28% had radiological progression of OA

 

Lonner et al JBJS Am 2006

- revision of 12 PFJR revised to TKR

- for progressive tibio-femoral OA or patella catching / maltracking

- good results

- all PS, no augments or stems required

 

Results Australian Joint Registry

 

7 year revision rate of 22.4%

- males and young age highest risk revision

 

Cause

- progression of disease 35%

- loosening 21%

- pain 11%

 

6.  TKR

 

Patella Baja

Patella Baja

 

Aetiology

 

Congenital

 

Acquired

- trauma

- post ACL reconstruction / TKR

- chronic quadriceps rupture

 

Issues

 

Decreases ROM

Associated with early OA of the PFJ

 

Diagnosis

 

Blackburne-Peel ratio at 30 degrees flexion

 

Patella Baja Blackburne Peele

 

Options

 

Excise lower third patella tendon

Patella tendon reconstruction with achilles tendon allograft

Tibial tubercle osteotomy and proximalization

Patellectomy

 

Proximalization fo the tibial tuberosity

 

Proximalization of Tibial tuberosity 1Proximalization tibial tuberosity 2

 

Patella BajaPost proximalization tibial tuberosity

Patella Fracture

Mechanism

 

Direct blow

- most common

 

Indirect

- forced knee flexion with foot fixed / maximally contracted quadriceps

 

Types

 

1.  Vertical

 

Patella Fracture Vertical

 

2.  Transverse

 

Patella Fracture DisplacedPatella Fracture Displaced AP

 

3.  Burst / Stellate

 

Patella Fracture Stellate

 

Management

 

Non operative

 

Indications

 

Vertical

- biomechanically stable

 

Undisplaced transverse fractures

- < 2mm

- extensor mechanism intact

- able to straight leg raise

 

Patella Fracture TransverseUndisplaced patella fracture

 

Operative

 

Indications

 

Displaced transverse fractures

 

Techniques

 

1.  TBW

 

Patella TBW LateralPatella TBW AP

 

2.  Cerclage wire +/- ORIF

- stellate fractures

 

3.  Lag screws

 

4.  Patellectomy

 

Indications

- unreconstructable fracture

 

Risks

- extension lag / weakness

- anterior instability

 

Gunal et al JBJS Br 1996

- patients with at least 5 fragments

- advocated VMO advancement

- additional medial parapatellar incision

- advance laterally and distally

- demonstrated improved strength and decreased lag

 

Patellectomy Lateral

 

Late Management

 

Malunion Patella Fractures

 

Partial patellectomy

- remove part of medial or lateral facet

- good functional and pain relief

 

Non Union Patella Fragment

 

Patella Fracture nonunionPatella Fracture NonunionPatella Fracture Nonunion CT

 

Patella Fracture Nonunion

 

 

Patella Instability

Background

Definition

Dislocated Patella

 

Repeated dislocation of patella with minimal trauma

- 15-20% of paediatric acute patella dislocations

- more common girls 

- often bilateral

 

Dislocation occurs unexpectedly when quadriceps contracted with knee in flexion 

 

Direction

 

Usually lateral

 

Medial is usually iatrogenic

- excessive lateral release

- lateral release for incorrect reasons

- overtightening of medial structures

 

Anatomy

 

Ossification

 

Usually one ossification centre usually that appears at age 3 & closes soon after puberty

 

Facets

 

Retropatellar surface has 7 facets

- 3 on lateral side

- 1 extra on medial side (odd facet)

 

Patella Medial and Lateral Facets

 

Lateral surface larger than medial

- lateral cartilage thicker than medial

- medial & lateral separated by median ridge 

 

Medial facet & odd facet are separated by another long ridge

 

Tracking

 

Tracking is dynamic 

- lateral in full extension

- more medial & central with flexion

 

Relies on normal static and dynamic stabilisers

 

Static Constraints

 

1.  Bony contours of femur

- prominence of LFC anteriorly

2.  Normal rotational profile

3.  MPFL is constant / static checkrein to patella

 

Dynamic Constraints

 

Quadriceps is dynamic stabilizer

- VMO fibers attach to patella at 65° angle

 

Biomechanics Goodfellow 1976

 

0°         No PF contact

 

20°       Most distal part patella contacts trochlea

 

0-30°    Median patella ridge lies lateral to the centre of the trochlea

 

30-60°  Patella moves medially to be centered in groove

 

60-90°  Deeply engaged in trochlear groove & is held by ST tension

 

90°       Entire articular surface contacts except odd facet

 

>90°    Patella tilts so that medial facet articulates with the MFC

 

135°    Odd facet contacts lateral border of MFC

 

Aetiology Patella Instability

 

Complicated / Multifactorial

 

Valgus malalignment

Ligamentous laxity

Insufficient medial structures (MPFL rupture / medial retinaculum laxity / VMO atrophy)

Tight lateral retinaculum

Trochlea dysplasia

Patella alta

Abnormal rotational profile (femoral anteversion / external tibial torsion)

 

Bony

- patella alta / baja

- trochlea / patella hypoplasia / dysplasia 

 

Soft tissue

- VMO atrophy / medial retinaculum laxity / torn MPFL

- tight lateral structures (capsule, retinaculum, ITB)

- ligamentous laxity

 

Alignment

- femoral anteversion

- external tibial torsion

- genu valgum

 

History

 

Pain 

 

Beware unrelenting pain

- chondral damage

- patella tilt / lateral patella syndrome

 

Instability

 

Traumatic vs. atraumatic onset

Direction of instability 

Age first dislocation

Subsequent dislocations

- mechanism, frequency

- ? voluntar

Treatment to date 

 

Effusions

 

Examination

 

Generalised ligamentous laxity  

 

Wynne-Davies Criteria

- positive if 3 of 5 bilateral signs

- hyperextension of the MCP joints parallel to  forearm 

- touch thumb passively to forearm

- elbows hyperextend beyond 0o

- knees hyperextend beyond 0o

- ankle DF > 45o

 

Patient Standing

 

Valgus Malalignment

 

Patella

 

1.  Squinting patella

- with femoral anteversion patellae point inwards when standing

 

2.  Grasshopper eyes

- patella sits high & lateral due to patella alta

 

Gait

 

In toeing

- internally rotated foot progression angle

- indicates femoral anteversion / tibial torsion

 

Patella Tracking

 

Patient sitting over side of bed

- flex and extend knee

- compare normal to abnormal side (if not bilateral)

 

J-sign

- lateral subluxation of patella as knee approaches full extension

- patella sharply deviates laterally in terminal extension 

- indicates some degree of mal-tracking

 

Patella J Tracking Enlocated in FlexionPatella J Tracking Extension

 

Knee Examination

 

Previous incisions

VMO wasting

Effusion

ROM

- exclude extensive mechanism tightness

- symmetrical heels to buttocks

 

Knee extended (3)

 

1.  Tenderness

- lateral retinaculum 

- retropatellar space

- Bassett's sign (tender medial epicondyle / acute MPFL avulsion)

 

2.  Clarke's Test / patella grind

- produces anterior knee pain with PFJ pathology

- compress patella and ask patient to contract quads

- very non specific test

 

3.  Patellar tilt test

 

Patella Tilt 1Patella TIlt Normal

 

Evaluates tension of lateral restraint 

- patient supine and relaxed with knees extended 

- examiner's thumb on lateral aspect of patella

- lateral edge of patella elevated from the lateral condyle and medial edge depressed 

 

Abnormal if unable to tilt lateral patella to horizontal

 

Knee flexed 30o over pillow (3)

 

1.  Q (quadriceps) angle 

 

Patella Instability Increased Q Angle

 

Measurement

- line from ASIS to centre of patella 

- line from centre of patella to tibial tuberosity

- angle subtended is Q angle 

 

Values

- normal 10o men, 15o women

- abnormal if > 15o in males and > 20o in females 

 

Causes increased Q angle

- femoral anteversion (squinting patellae) 

- external tibial torsion

- lateral tibial tuberosity

- genu valgum 

 

2.  Sage mobility

 

Test at 30o flexion

- move patella medially and laterally

- graded in number of quadrants patella displaces 

- > 50% displacement = insufficient restraints 

 

Patella Lateral HypermobilityPatella Medial Hypermobility

 

Lateral glide 

- >3 quadrants suggests incompetent med restraints 

 

Medial glide

- > 3 suggests incompetent lateral restraint / hypermobile patella

- < 1 suggests tight lateral retinaculum

 

3.  Apprehension test (Fairbank)

 

Patient supine and relaxed 

- place relaxed knee at 30 degrees & push patella laterally as flex

- can also do with knee flexed over edge of bed

- positive test is a quads contraction & apprehension

 

Rotational Profile

 

Prone

 

1.  Lateral border of feet

- if curved, metatarsus adductus 

 

2.   External tibial torsion

- intermalleolar axis > 30o

- Thigh foot angle > 15o

 

Thigh Foot Angle 20 DegreesThigh Foot Angle 35 Degrees

 

3.  Femoral anteversion

- IR > 45o

- Gage's trochanteric angle > 15 - 20o

 

Increased Femoral Anteversion

 

Investigation

AP / Long Leg Views

 

Quantify Valgus Malalignment

 

Patella Instability Long Leg Views Valgus MalalignmentValgus Knee

 

Lateral Xray

 

1.  Assess Patella Alta

 

30o flexion

 

A.  Blumensaat's line / Inaccurate

 

Knee flexed to 30o

- line should just touch inferior pole of patella

- pole above line - alta

- pole below line - baja

 

Patella Height Normal Blumensaat's LinePatella Alta Blumensaat's LinePatella Alta Blumensaat's Line

 

B.  Blackburn-Peele ratio / Best and Most accurate

 

Distance between tibial and patella articular surface

- divided by patella articular surface

- patella alta > 1

 

Patella Baja Blackburn PeelePatella Alta Blackburn Peele

 

C.  Insall ratio

- less accurate, probably because more difficult to measure

- ratios also difficult to remember and calculate

- length of patella tendon v length patella

- patella alta LT : LP 1.2

- patella baja LT : LP <1

 

Patella Height Normal Insall RatioPatella Alta Insall Ratio

 

2.  Assess Trochlea Dysplasia

 

Dejour Crossover Sign

- lateral x-ray at 30o with condyles superimposed

- identify base of trochlea

 

Normal

- clearly defined trochlea groove

 

Trochlea Anatomy NormalTrochlea Normal Anatomy Diagram

 

Abnormal / Crossover

- line of floor of trochlea crosses lateral lip of condyle

- indicates trochlea is deficient proximally

 

Trochlea Crossover

 

Trochlea depth

- < 8 mm shallow

 

Dejour grading system 1 - IV

 

Patellofemoral view

 

1.  Skyline view

 

Technique

- 45o

- shoot throught film

 

Look for

- OCD

- bony avulsion MPFL

 

MPFL Bony Avulsion

 

2.  Laurin view / patella tilt

 

Technique

- knee 20o, camera at bottom

 

Assessment patella tilt

- first line anterior aspect both condyles

- line lateral facet

- should diverge laterally

 

Patella tilt

- lines parallel or open medially

 

Patella Laurin View NormalPatella Tilt Laurin ViewPatella Tilt

 

3.  Merchant view / patella subluxation

 

Technique

- 40o flexion, beam from top

- patella should be well engaged

- central ridge should lie at or medial to bisector of the trochlea groove

 

Congruence angle

- draw sulcus angle

- bisector of sulcus angle

- line to central ridge of patella

- should be - 10o (i.e. medial)

- lateral direction is positive

 

Normal

 

Patella non SubluxedPatella Medial Congruence Angle

 

Subluxed

 

Patella Lateral SubluxationPatella Lateral Congruence AnglePatella Subluxation

 

4.  Trochlea dysplasia

 

Normal

 

Patella Normal TrochleaPFJ Normal Sulcus Angle

 

Sulcus angle

- > 140o flattened

 

Trochlea Dysplasia

 

5. Excessive Lateral Pressure Syndrome

 

Ficat and Hungerford

 

A.  Indirect signs of excessive lateral pressure

- thickened subchondral plate

- increased density lateral facet

- lateralisation of trochlea

- medial facet osteoporosis

- hypoplasia lateral condyle

 

Patella Excessive Lateral Pressure 1Patella Excessive Lateral Pressure 2

 

B.  Indirect signs of excessive lateral ligament tension

- fibrosis lateral retinaculum

- calcification lateral retinaculum

- lateral osteophyte

- bipartite patella

- lateral facet hypoplasia

- medial compartment hypoplasia

 

Patella Excessive Lateral TensionPatella Excessive Lateral Pressure

 

CT

 

1.  Skyline View

 

Assess for

- lateral tilt

- subluxation

- trochlea dysplasia

 

PFJ Axial CT

 

2.  Lateralisation of tibial tuberosity

 

TTTG CT

 

Jones et al Skeletal Radiology

 

Superimpose 2 axial slices

 

A.  Axial slice of trochlea

- line of posterior condyles

- line perpendicular through trochlea

 

Axial CT PFJ

 

B.  Slice through tibial tuberosity

- perpendicular line through TT

 

CT Axial Tibial Tuberosity

 

Calculate Distance between two points / TTTG

 

10 - 15 mm normal, > 15 abnormal

 

Pandit et al Int Orthop 2011

- normal 10 +/-1 on MRI

 

MRI

 

Articular Cartilage Damage

MPFL integrity

OCD

Loose Bodies

 

Arthroscopy

 

Assess chondral surfaces

Removal of Loose Bodies

Tracking

- not particularly valid

- patient is relaxed / knee filled with fluid

Management

Non-operativePatella Instability MPFL and TTT AP

 

Results

 

90% respond 

- very important

- 6 - 12 months minimum before offering surgery

 

Physiotherapy

 

1.  Stretches

- quads stretches

- ITB

- lateral retinaculum

 

2.  Quads strengthening

- avoid pain

- PFJ contact pressures lowest from 0-30o

- short arc quads extension

- closed chain VMO exercises

 

3.  Taping / bracing

- patella cut out brace

- little hard evidence

- may provide proprioceptive feedback

 

Operative

 

Indications

 

For failure of non-operative treatment 

- patella tilt with lateral patella pain

- recurrent instability

 

Options

 

Depends on pathology

- assessment and investigation critical for deciding treatment

 

1.  Isolated Patella tilt

 

Indications

- clinical and xray patella tilt

- no instability / malalignment

- excessive lateral pressure syndrome

 

Techniques

 

1.  Arthroscopic lateral release

- knee in extension

- camera in AM portal

- hook diathermy in AL portal

- 5mm lateral to patella / 1cm superior to patella / down to anterolateral portal

- release retinaculum under vision

- must ensure SLGA coagulated / can visualise

- let down tourniquet at end of procedure

- ensure can evert patella 90o at end

 

2.  Smiley knife release

- arthroscopy

- insert in AL portal

- divide retinaculum by feel

 

Post op

- drain 24 hours

- protect for 1 week

 

Results

 

McGinty et al Clin Orthop 1981

- 32/39 G/E results

 

Complications

 

A.  Haemarthrosis

- can be major / problematic

- insert drain, splint and minimise activities first few weeks

- manage via early washout / insertion drain

 

B. Medial subluxation

- extending release too far into VL

- performing lateral release when have ligamentous laxity and instability

 

Patella subluxation / recurrent dislocation

 

Issues

- must have had long non operative period

- treatment depends on cause

- different treatment options in skeletally immature

 

Treatment algorithm

 

1.  Recurrent subluxation + normal alignment (TTTG < 15 - 20)

- lateral release (only do if patella tilt / tight laterally or will dislocate medially)

- MPFL reconstruction / VMO advancement / medial reefing

 

2.  Recurrent subluxation + malalignment (TTTG > 20)

- above + add TTT (tibial tuberosity transfer)

- Roux-Goldthwaite instead of TTT if physis open

 

3.  Above + Excessive femoral anteversion

- consider DRFO (derotation femoral osteotomy)

 

4. Above + Excessive external tibial torsion (> 45 degrees)

- consider tibial derotation osteotomy

 

5.  Trochlea dysplasia

- trochleoplasty

 

5.  Patella alta

- distalise TT

 

Surgical Algorithm

 

1.  Perform lateral release

- rarely needed

- most patients are ligamentous lax / hypermobile patella

- may be needed in chronic setting or if congenital

 

2.  Perform TTT (if TTTG > 20)

- incision over TTT

- medialise at least 1 cm

- ensure some element of Fulkerson / anteriorise

- can distalise if patella alta

- secure with screws (2 x small fragment usually sufficient)

- reassess stability

 

3.  MPFL reconstruction (with TTT, or if TTTG < 20)

- acts as checkrein to lateral displacement

- usually harvest hamstring autograft

- medial incision

- beware overtightening (will give pain) / patella fracture (drill holes in patella)

- reassess for stability

 

4.  Lateral Trochlea Elevation

- still unstable after above operations

- small lateral incision

- beware fracturing lateral femoral condyle

- need to be able to take bone graft from iliac crest

 

Tibial Tuberosity Transfer

 

Contraindication

 

Open Physis

 

Theory

 

A. Medial displacement corrects Q angle

- must correct Q angle < 10o

- at least 1 cm

 

B. Anterior displacement unloads PJF

 

C. Distal displacement corrects patella alta

 

Types

 

Hauser distalisation

- for patella alta

- operation in isolation had disappointing results

- get posteriorisation tubercle and increased forces across PFJ

 

Fulkerson

- anteromedial transfer

- osteotomy lateral to medial

- direct osteotomy anteriorly

- unloads PJF

 

Fulkerson Osteotomy APFulkerson Osteotomy LateralFulkerson Osteotomy Skyline

 

Elmslie-Trillat

- medialisation

- no posterisation

 

Surgical Technique of TTT

 

Technique 1

- direct osteotomy with oscillating saw lateral to medial

- initial incision slightly lateral of midline over Tibial tuberosity

- lateral incision in periosteum

- osteotomy 1.5 cm deep, 6 cm long

- angle osteotomy 45 degrees / use k wires to guide

- attempt to leave medial and distal periosteum intact for stability

- minimum medial transfer is 1 cm, usually 18 - 20 mm

- fix with two screws

- if want to distalise for patella alta, performing distal step cut, and distalise 6 mm

- never make transfer posterior

 

Tibial Tuberosity Transfer

 

Technique 2

- use reciprocating saw

- cut down from the top, behind the PT

- 4 cm long

- leave intact distally

- use 3.5 mm drill to perforate distal attachment laterally

- can then swing the TT medially on distal / medial pivot

- secure with singe 4.5 mm bi-cortical lag screw

 

Consider patella cartilage

- combine with cartilage procedure

- microfracture / MACI / de novo

 

Patella instability cartilage loss

 

Results

 

Caton and Dejour Int Orthop 2010

- TTT in 61 knees

- 76.8% stability

 

Cossey et al Knee 2005

- 19 patients with TTT / MPFL reconstruction

- no redislocations

 

Skeletally Immature

 

Roux-Goldthwaite

 

Indications

- skeletally immature with malalignment

 

Technique

- lateral half PT rerouted

- under medial PT

- stitched to MCL / sartorius

 

Technique Modification

 

Take medial half patella tendon

- suture to MCL

 

PT transfer + MPFL

- incision midway between PT and MCL

- identify patella tendon

- divide in two

- sharp dissection of medial half off bone

- dissect medially

- divide fascia and retinaculum to expose MCL

- suture to MCL with 2.0 non absorbable sutures

- through same incision can harvest hamstrings for MPFL reconstruction

 

Results

 

Fondren et al JBJS Am 1985

- 43/47 G/E results

 

Medial Operations

 

1.  MPFL reconstruction

 

Indication

- patient with history initial traumatic dislocation

- also indicated in patient with laxity to act as a check rein

 

Grafts

 

1.  Y Graft

- double ST autograft into Y

 

2.  Single limb free semitendinosus autograft

- limb to patella via endobutton

 

MPFL Reconstruction 1MPFL Reconstruction 2

 

Schottle's Point

 

Schottle AJSM 2007

- cadaveric study

- 1 mm anterior posterior cortex

- 2 mm distal to MFC origin

- above blumensaats

 

Schottles Point

 

Technique

 

A. Patella fixation

- incision along medial patella

- 2 drill holes in patella

- attach ends of graft, pass into patella, secure with anchor of choice

- pass graft superficial to capsule

 

B. Femoral fixaiton

- best to use II to find point

- stem between medial epicondyle and adductor tubercle

- Schottle's Point

- drill wire across femur, drill hole for fixation screw

- pass doubled graft into tunnel

- set at 30o flexion

- ensure doesn't dislocation laterallly

- don't overtighten

- secure with screw

 

Xrays 1

 

Tunnel too anterior / tight in flexion

 

Patella Instability MPFL and TTTPatella Instability MPFL and TTT Lateral

 

Xray 2

 

Finding Schottles Point

 

Schottles pointFemoral Fixaiton MPFL

 

Results

 

Nomura et al J Arthroscopy 2006

- recurrent dislocation, no malalignment

- 83% G/E results

- no redislocation at  2 year follow up

 

Howells JBJB Br 2012

- 211 procedures in 193 knees

- all TTTG < 18

- most moderate trochlea dysplasia

- no redislocations at 16 months

 

Shah et al AJSM 2012

- Systematic review MPFL

- 26% complication rate

- 4/629 (0.6%) fractures

- 26/629 (4%) stiffness

- 23/629 (3.7%) failure rate

 

2.  Medial imbrication

 

Indications

- MPFL needs to be intact or won't work

- laxity / stretched / attenuated structures

 

Technique

 

Insall procedure

- medial flap sutured 1 cm over lateral flap

 

Results

 

Scuderi et al JBJS Am 1988

- combined with lateral release

- normal and abnormal Q angle

- 42/52 G/E 81%

 

Barber et al Arthroscopy 2008

- TTT + medical plication in 34 knees

- 91.4% stability

 

Zhao AJSM 2012

- RCT MPFL v medial plicaiton

- 100 patients

- recurrent instability 7% v 16%

- better Kujala scores in MPFL

 

3.  VMO advancement

 

Madigan procedure

- VMO detached and advanced laterally and distally

- sutured to fascia on patella

 

Trochleoplasty

 

Indication

- trochlea dysplasia

- if after MPFL and TTT the patella still unstable at end of case

 

Techniques

 

1. Dejour Trochleoplasty

- lift up anterior aspect femoral condyles

- deepening of trochlea

- replacement of LFC

- risk of chondral fracture / AVN / non union / displacement

 

Utting et al JBJS Br 2008

- 50/54 92% 

- combined with other procedures as required

 

2.  Elevate lateral edge of lateral femoral condyle

- insert osteotome

- gently elevate without fracturing chondral surface

- insert 2 - 3 mm of iliac crest bone graft

- no need for stabilisation

 

Results

 

Nelitz et al AJSM 2013

- trochleoplasty + MPFL in 26 knees

- no redislocation, no complications

- 96% statisfied

 

Tibial Derotation Osteotomy

 

Indication

- excessive external tibial torsion > 45 degrees

- 1 / 5000 people

 

Tibial Derotation Osteotomy

 

Tibial Derotation OsteotomyTibial Derotation Osteotomy Lateral

 

Results

 

Drexler et al KSSTA 2013

- good outcome for 15/17 knees

 

Chronic Dislocation

 

Chronic Patella Dislocation 1Chronic Patella Dislocation 2Chronic Patella Dislocation

 

Chronic / congenital

- patella subluxed out of joint

- patella alta

- treat with identical principles

- lateral release / TTT / MPFL reconstruction

 

Chronic Patella DislocationChronic Patella DislocationChronic Patella Dislocation 5

Patella Tendon Rupture

Epidemiology

 

Usually occurs in young people

- often previous history of tendonitis ± steroid injections

 

Location

 

Usually at level of inferior pole of patella

- less common at tibial tubercle

- mid-substance ruptures rare

 

Clinical

 

Severe pain

Palpable defect

Extensor deficit / unable to SLR

 

Xray

 

Patella alta / high riding patella

 

Patella Tendon Rupture

 

Distal Pole Patella Fracture

 

Patella Tendon Bony Avulsion

 

MRI

 

In chronic cases may only detect that tendon not attaching to distal pole patella

 

Patella Tendon Tear MRI

 

Acute Management

 

Requires operative repair

 

Technique

 

Problem

- avoid baja caused by overtightening patella tendon

- drape patient in such a way so as to palpate other PT

- compare patella heights at end of case

 

Multiple Bunnell / Krackow Sutures to Patella Tendon

- 2 non absorbable

- drill holes through patella ( 3 - 4)

- pass sutures and tie 

- can augment with box fibrewire

 

Patella Tendon Rupture Post Repair Intraosseous Sutures and Box suturePatella Tendon Rupture MRI Post Repair

 

Can reinforce with box wire loop

- large gauge wire 18G

- drill hole in tibial tuberosity

- transverse drill hole in patella

- pass in square and tie

- protects patella tendon

- problem is will break / irritate / need removal

- only do if concerned re repair

 

Patella Box Wire APPatella Box Wire LateralPatella Box Wire Broken APPatella Box Wire Broken Lateral

 

Test repair at end of case

- should be able to do some limited ROM

 

Patella Tendon AvulsionPatella Tendon ORIF

 

Augmentation

 

1. Semitendinosus autograft

- leave semitendinosus attached distally

- pass through distal pole patella

- reattach to tibia on lateral side

 

2.  Patella tendon Allograft

 

3.  Lars Ligament

 

Chronic Rupture

 

Reconstruction

 

Case: Reconstruction with tendoachilles allograft, bone block in tibia

 

Chronic Patella Tendon Rupture XrayChronic Patella Tendon Rupture MRIPatella Tendon Graft

 

Chronic Patella Tendon Rupture 1Chronic Patella Tendon Rupture 2Chronic Patella Tendon Rupture 3

 

Chronic Patella Tendon Rupture 4Chronic Patella Tendon Rupture 5

 

Chronic Patella Tendon Rupture Post Op LateralChronic Patella Tendon Rupture Post OP AP

 

Case: Reconstruction with Hamstring Autograft

 

Chronic patella tendon ruptureChronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Chronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Chronic patella tendon rupture Hamstring ReconChronic patella tendon rupture Hamstring Recon

 

Patellar tendonitis

Definition

 

Patellar Tendinitis

 

Epidemiology

 

Most common in athletes

- especially if involved in running, jumping and kicking

- over use injury

 

Basketball players

 

Aetiology

 

Chronic overload v inferior patella impingement

 

Schmidt et al Am J Sports Med

- dynamic MRI in patients with jumper's knee v controls

- no evidence of impingemnt

- concluded that chronic overload main cause

 

Incidence of inferior patella spurs

- likely part of pathology

 

Clinical Features

 

Insidious onset of pain at inferior pole of patella

- initially after activity only, worse as cools down

- localised tenderness at inferior pole

- may progress to rupture

 

X-ray

 

Usually normal

 

May see

- traction spurs

- calcification of patella tendon

 

Patella Tendon CalcificationPatella Spur

 

MRI

 

Cyst / Degeneration

 

Jumpers Knee MRI

 

Traction spurs / calcification / ossicles

 

Patella Tendonitis Calcification MRIPatella Tendon Calcification MRIPatella Spur MRI

 

Non-operative

 

Activity modification

 

Rest 6/52

- warm up & stretching

- ice & NSAIDS

 

Sport rehabilitation protocol

 

Concentration on eccentric exercises

- decline squats on a 25o decline board

 

Jonsson et al B J Sports Med 2005

- RCT of concentric v eccentric quads exercises

- superior results with eccentric

 

Engebretsen et al JBJS Am 2206

- RCT of eccentric rehab v surgery

- no advantage surgery

- recommended minimum 12 weeks non operative treatment in all cases

 

HCLA

 

Contra-indicated

 

Platelet Rich Plasma

 

Fillardo et al Int Orthop 2010

- compared three injections PRP 2 weeks apart in 15 chronic patients

- compared wth 16 patients treated with physiotherapy alone

- significant improvements in PRP group

 

Charousset AJSM 2014

- 3 consecutive US guided PRP into tendon defect

- sucess in 21 / 28 athletes

 

ECSW

 

Vulpiani et al J Sports Med Phys Fitness 2007

- 4 sessions every 2 days

- 73% successful in all patients

- 87.5% successful in athletes with return to sport at 6 weeks

 

Operative

 

Indications

 

Fails to resolve & interferes with activity

 

Technique

 

Arthroscopy

 

1.  Resection fat pad

2.  Resection posterior inflammed portion of tendon

3.  Careful burr resection of inferior pole patella

- 1 - 2 mm

- does't affect patella tendon insertion

- removes source of impingement

- likely stimulates healing process

 

Results

 

Lorbach et al Arthroscopy 2008

- arthroscopic debridement inferior pole patella in 20 patients

- 18/20 good or excellent results

 

Pascarella AJSM 2011

- arthroscopic debridement undersurface of tendon / tendinopathy

- excise distal pole

- success in 66 / 73 knees

- RTS by 3 months

 

 

 

 

Quadriceps Rupture

Epidemiology

 

Usually occurs in patients over 60

- due to decreased vascularity & collagen weakness

 

Younger patient on steroids / growth hormone

 

Occasionally occurs in young athlete with excessive contracture

 

Aetiology

 

Often preceded by quadriceps tendinosis

 

Quadriceps Tendinosis MRIQuadriceps Tendinosis 2

 

Location

 

1.  Avulsion of quadriceps tendon from superior patella

2.  Rupture of belly of rectus femoris

3.  Rupture at musclulotendinous junction in athletes

 

Clinical

 

Quadriceps Tendon RuptureQuads Tear

 

Palpable gap in tendon

Haemarthrosis

 

Extensor lag

- function usually good if tear incomplete

 

Extensor Lag

 

Diagnosis can be missed once acute features settle

 

Xray

 

Patella Baja

 

Quadriceps Rupture

 

MRI

 

MRI Chronic Quadriceps RuptureQuads rupture MRI

 

Management

 

Options

 

Incomplete

- immobilise for 4/52 in extension

- then rehabilitate

 

Rectus Femoris Avulsion 1Rectus Femoris Tear 2

 

Complete 

- surgical repair

 

Athlete 

- surgical repair

 

Surgical Technique

 

Position

- patient supine

 

Midline incision

- expose quadriceps

- mobilise tendon / release from subcutaneous tissue

- debride insertion on patella

 

Quads Repair 1Quads Repair 2Quads Repair 3

 

Drill holes in patella

- pass sutures with houston suture passer

- pass large non absorbable suture

- multiple times through tendon

 

Quads Repair 4Quads Repair 5Quads Repair 6

 

Other option

- suture anchors in distal patella

 

Post operative rehab

- keep in extension 6 - 8/52

 

Late presentations / Rerupture

 

Options

- quadriceps turndown

- quadriceps VY advancement

- fascia lata graft

- Lars graft reinforcement

 

Note: Patella Baja with chronic rupture

- patient may develop patella baja

- with chronic injuries / failed injuries

- may need to perform tibial tuberosity osteotomy

 

Failed Quadriceps Repair

 

Tibial Tuberosity OsteotomyTibial Tuberosity Osteotomy 2

 

 

Quads Repair Tibial OsteotomyQuads Repair Tibial Osteotomy 2

 

Revision Quadriceps Repair with Tibial Tuberosity Osteotomy

 

Allograft Reconstruction

 

Chronic Quads TearQuads Recon 1Quads Recon 2

 

Quads Recon 3Quads Recon 5

 

Quads Allograft Final 1Quads Allograft reconstruction 2

 

Tendo-achilles

- flat portion oversewn proximally

- two limbs passed through drill holes in patella

- sewn onto themselves

 

 

Sinding - Larson - Johanssen

Epidemiology

 

Active pre teen boy

- activity related pain

- common in high jumpers

 

Diagnosis

 

Fragmentation / calcification of inferior pole

- repetitive traction injury where PT inserts

- tender at this point

 

Stages 

 

I     Normal

II    Ca inferior pole irregularity

III   Coalesce Ca inferior pole

IV    Incorporation of Ca

 

DDx

 

Patella stress fracture

Sleeve fracture

Type 1 bipartite patella

Jumper's knee in older patient

 

Management

 

Self- limiting 

- symptomatic treatment

- can use cast immobilisation

 

Rarely surgical excision