Rotator Cuff

Calcific Tendonitis



Mid-substance calcification of the rotator cuff

- part of a metaplasia secondary to hypoxia


Supraspinatous CalciumSupaspinatous Large Deposits




2 groups of patients


1.  Degenerate Calcification


Dystrophic calcification of degenerative cuff

- necrotic fibrillated fibres act as nucleus for calcium

- occurs at the cuff insertion

- usually smaller


These patients do not have calcific tendonitis

- older patient group

- different histology


2.  Calcific Tendonitis




Reactive Hypoxic Calcification Theory


Cells undergo metaplasia to fibrocartilaginous cells

- fibrocartilage cells accumulate intracellular calcium


Codman proposed cuff hypoxia as the causative factor




1.  Pre-Calcific stage


Fibro-cartilaginous metaplasia

- tenocytes transformed to chondrocytes

- hypoxia


2. Calcific Stage


A. Formative Stage 

- no or chronic pain

- "Chalk" appearance

- calcium crystals in matrix vesicles

- crystals may be in the form of phosphates / carbonates / oxalates / hydroxyapatite


B. Resting Stage

- fibrocartilage surrounds deposits


C. Resorptive Stage

- acute pain

- "Toothpaste" or fluffy appearance

- macrophage resorption / calcium granuloma


3. Post-Calcific Stage


Area heals to scar

- granulation tissue fills space left by calcium

- Type III collagen -> Type I




Accounts for 10% all consultations for painful shoulder


Peak 40 years

- diabetes

- F > M 


SS most common tendon

- IS less common

- SSC rare


Asymptomatic patients can have cuff calcium on xray


Clinical Presentation


Usually acute pain

- Resorption Stage

- background of absent to mild chronic pain of the Formative Stage


Patients may present to ED

- severe pain


DDx infection




Cuff / Biceps Tendinopathy

Freezing Shoulder

Brachial Neuritis

Septic Shoulder

Gout / CPPD





Calcific Tendonitis APCalcific Tendonits Lateral


Calcium typically supraspinatous

- mid-cuff

- 1-1.5 cm from insertion

- 1-1.5 cm in size


ER AP Xray

- shows SSC


Subscapularis CalciumSubscapularis Calcium Lateral


IR AP Xray

- shows IS & Tm


Painful Resorptive / Type 1

- fluffy, with poorly defined margin

- irregular density

- can rupture into bursae as a crescent like streak


Chronic Formative / Type 2

- discrete, well defined deposit

- uniform density




Low signal on T1 

Oedema on T2


Shoulder MRI T1 Calcific TendonitisShoulder MRI Calcific Tendonitis T2



- more sensitive than Xray ~100%


Ultrasound Calcific TendonitisUltrasound Calcium Supraspinatous




Check serum glucose / uric acid & iron




Non operative Management





- may impair resorption

2.  HCLA

- no effect NHx

- may impair resorption

3.  ECSW Therapy

4.  Ultrasound guided needling and aspiration


Extracorporeal shock wave therapy


Extracorporeal Shock Wave Machine


Peters Skeletal Radiol 2004


- 90 patients

- treatment group complete resolution in 86%, reduction in size in 13.4%

- control group 0 disappeared completely, 9% partial reduction

- significant reduction in pain and improvement in function at 4 weeks

- no adverse affects


Effectiveness directly related to energy

- 0.44 mJ/mm3


Needle aspiration and irrigation



- drain a substantial portion of the calcium

- stimulate resorption of remainder



- resorption phase (soft, toothpaste material)



- small deposits

- formative phase (hard, chalky material)



- US guided procedure under LA

- one needle into deposit, inject saline

- one needle into deposit, aspirate

- create inflow outflow

- want minimal punctures for this to work

- distinguish Formative vs Resorptive



- very painful for first 2-3 days




Aina et al Radiology 2001

- excellent results in 74%


Serafini et al Radiology 2009

- non randomised controlled trial

- patients treated better at 1 month / 3 months and 1 year

- no difference long term


Krasny JBJS Br 2005

- prospective RCT

- improved results by performing US needling followed by ECSW therapy

- c.f. ECSW alone


Operative Management



- severe disabling symptoms > 6 months

- failure of needling / ECSW





- unknown

- alone has been shown to improve patients symptoms

- do so if any acromial or GT evidence of impingement


Marder et al J Should Elbow Surg 2011

- retrospective comparision of 2 groups

- calcium excision v excision + SAD

- SAD much longer time to return to non painful shoulder activity





Arthroscopic and mini open



Arthroscopic Technique


Find Calcium

- remove bursa with shaver

- deposit may be obvious

- however may have to use needle

- get cloud of calcium when find deposit


Calcium NoduleCalcium NeedleCalcium IncisionCalcium in Tendon


Attempt to longitudinally split tendon

- curette calcium

- lavage +++ to prevent secondary stiffness

- usually don't repair tendon to prevent stiffness


May need to remove entire diseased section and repair


Calcific Tendonitis Arthroscopy 1Calcific Tendonitis Arthroscopy 2Calcific Tendonitis Arthroscopy 3Calcific Tendonitis Arthroscopy 4




Secondary stiffness



- secondary to calcium deposits

- careful shoulder washout at the end of the case



Cuff Tear Arthropathy

DefinitionRotator Cuff Arthropathy


Chronic massive rotator cuff defect

- uncovered humeral articular cartilage

- high riding humeral head

- abrasion by undersurface of coracoacromial arch





- introduced term "cuff tear arthropathy"

- included significant rotator cuff diagnosis & arthritis in older patients

- especially women

- synovial fluid contained calcium phosphate crystals + proteases




Crystal induced arthropathy

- hydroxyapatite-mineral phase in altered capsule, synovium or degenerate articular cartilage

- induce synthesis of proteolytic enzymes

- destruction of cartilage via collagenase, stromeolysin

- origin of crystals unclear

- 1° or 2° to arthritis

- erosion of head begins superiorly rather than centrally


Cuff tear theory

- loss of cuff leads to mechanical and nutritional alterations in shoulder

- due to loss of closed joint space and altered range of motion




4% of massive cuff tears go on to arthroplasty



- tears with unbalanced force couplet go on to arthropathy 

- massive tear that are balanced & / or above equator don't go onto to arthropathy




Women > men

60% bilateral




Recurrent swelling

Loss of Motion

Night pain




1.  Superior migration of head 

- defined as AHI / acromiohumeral interval of 7mm or less


Humeral Head Superior Migration


2.  Collapse of proximal head articular surface 


3.  Proximal humerus becomes "Femoralized" 

- erosion of greater tuberosity


4.  Coracoacromial arch becomes "acetabularized"

- often articulates with acromion

- periarticular soft tissue calcification


Acromial Acetabularisation




RC Arthropathy CT





- no superior migration

- beard osteophytes






Often appropriate 

- many patients only mild symptoms

- patients elderly

- accept limited ROM

- analgesia


Operative Management


1.  Acromioplasty & tendon debridement 


Not indicated with superior migration

- can consider biceps tenotomy if still intact


2.  Arthrodesis


Poorly tolerated in elderly 

- significant pseudoarthrosis & re-operation rate in osteoporotic bone

- reserve for those with non functioning deltoid


3.  TSR 


Increased loosening of glenoid component if TSR

- superior migration of head due to unopposed deltoid

-"rocking horse" phenomenon 


4.  Hemiarthroplasty



- < 70

- intact CA arch

- anterior deltoid muscle



- do not oversize head

- can cut in some valgus to allow articulation with acromion

- correct size allows arm to lie freely across abdomen

- head to translate 50% posterior / anterior / inferior

- subscapularis to be re-attached without bow stringing

- margin convergence of cuff as possible for force couplet

- reattach CA ligament to prevent superior escape





- 18 of 21 satisfactory

- good pain relief

- ROM often not improved



- concept of limited goals category

- 20° of ER and 90° of forward elevation


Poor prognosis

- previous acromioplasty

- previous division CA ligament

- deltoid insufficiency


5.  CTA Humeral Head


Depuy Cuff Tear Arthropathy

- arc of surface > 180o

- allows articulation of lateral head with acromion

- increased articulation in abduction and ER


CTA HemiarthroplastyCTA Head APCTA Head 2


6.  Reverse TSR



- > 70

- functioning deltoid



- medialises the centre of rotation

- increases lever arm for deltoid

- semiconstrained - prevents superior migration

- deltoid acts to stabilise shoulder






Arthroscopic Acromioplasty




- beach chair / lateral

- water pump, adrenaline in bags

- block pre-op useful as easier to control BP

- often inject the SAD with combination of LA with A prior to scope


Posterior portal

- 2 cm inferior, 1 cm medial

- soft spot between IS and Tm


Enter subacromial space

- sweep to clear adhesion

- saline on pump at 30 - 40 - 50

- keep BP  100 - 110

- can increase pump pressure to 60 - 80 if needed in short bursts


Midlateral portal

- spinal needle

- 3cm distal to anterior acromion

- midpoint clavicle

- slightly lower to aim up



- with shaver


Arthroscopic Bursectomy


Electrocautery / Shaver

- clear periosteum / coracoacomial Ligament off acromion

- avoid deltoid as bleeders

- beware thoroaco-acromial artery in CA ligament medial and inferior to acromion

- spinal needle ACJ to mark medial limits

- need to see anterior and lateral acromion


Arthroscopy Type 3 AcromionShoulder Scope Large Acromial Spur



- 5.5mm burr

- multiple techiques

- 5mm deep resection at midpoint clavicle

- taper anteriorly

- must ensure lateral edge is cleared


Arthroscopy Post AcromioplastyArthroscopy Cleared Subacromial Space


Residual Lateral Acromial Spur






DefinitionLateral Acromial Spur


Painful impingement of rotator cuff

- on anterior 1/3 of Acromion, CA ligament & ACJ

- causes tendinosis of the RC


Anatomy Subacromial Space


1.  Roof / CA Arch

- acromion

- CA ligament

- coracoid process

- ACJ is superior & posterior to CA ligament


2.  Floor 

- GT & superior aspect head

- rotator cuff





- extrinsic and intrinsic theories


1.  Extrinsic / Extra-tendinous / Bursal sided tears


CA arch impinges on RC

- true impingement syndrome

- causes tendinosis of the cuff




A.  Subtle GH Instability

- relationship poorly understood

- respond poorly to acromioplasty

- alteration in dynamics of shoulder


B.  Internal Impingement Posterior / Superior Glenoid


Described by Davidson 1997

- throwing athletes

- impinge in abduction & ER

- SS impinges on posterosuperior rim of glenoid 

- normally humeral head translates posterior in glenoid 

- this may be lost with instability or laxity of throwing athlete

- alternatively may be caused by posterior capsular tightness


See Miscellaneous/Throwing Athlete


C. Degeneration ACJ


OA Spurs


D.  Acromion Morphology


Neer = impingement on anteroinferior acromion 


E.  Os Acromiale

- mesoacromion most common

- hypermobile unfused epiphysis

- tilts anteriorly

- 1-15% normal population

- increased incidence with impingement


F.  CA Ligament Spurs 


Develop calcium in tendon


G.  CA Ligament Impingement

- common

- "Snapping shoulder"

- in flexion & IR

- SS & Biceps impinge on it

- Neer recommends division


H.  Coracoid Impingement

- less common

- subscapularis impingement between coracoid and LT

- may be exacerbated by anterior instability

- more medial pain with arm flexed, adducted and IR

- find SSC partial tears on arthroscopy


Coracoid Impingement Lateral Coracoid


2.  Intrinsic / Intra-tendinous / Articular sided tears


2° to bursal thickening or intrinsic problem in cuff

- ? Now thought to be most common




1. Muscle Fatigue

- overloaded weak muscles

- eccentric tension load

- associated with proximal humeral migration


2. Shoulder Overuse

- soft tissue inflammation

- repetitive microtrauma

- athletes / manual labourers


3. Degenerative Tendinopathy

- 1° intrinsic degeneration of RC

- ? hypovascularity

- increasing incidence with age




Impingement Zone 

- centered on supraspinatus tendon insertion

- Codman's "Critical Zone" 1cm from insertion

- zone of hypoperfusion


Neer's Pathological Classification


Stage I

- reversible

- oedema & haemorrhage

- < 25 years


Stage II

- irreversible change

- fibrosis & tendinitis

- 25-40 years


Subdivided by Gartsman

- Stage IIA = No tear

- Stage IIB = Partial thickness tears


Stage III

- > 40 years

- chronic

- partial & full thickness tears


Acromial Morphology


Bigliani / Assess on Supraspinatous Outlet View / Scapula Lateral


Type I:  Flat

- 20% of normal population


Type 1 AcromionType 1 Acromion


Type II:  Curved

- 40% of normal population


Type 2 Acromion


Type III:  Hooked

- 40% of normal population

- 80% of RC tears


Type 3 AcromionAcromion Type 3Acromial Spur Type 3


Cadaver study

- 30% of all cadavers had a full thickness cuff tear

- 75% type III & 25% type II & 3% type I


Morphology does change with age

- Spur more common > 50 years

- ? 2° event to cuff process

- most hooks appear to be acquired & lie in CA ligament 




Painful arc


Weakness overhead


If < 40 years look for instability




Painful Arc

- 70-120°

- > 120° - ACJ OA / terminal phase pain



- limitation of IR may suggest posterior capsular tightness


Neer Impingement Sign

- stabilize scapula from behind patient

- passively elevate arm in scapula plane

- pain between 70-120°


Hawkins Modification

- IR humerus at 90° flex


Neer Impingement Test 

- LA in SAD

- abolish pain & test for cuff tear / weakness



- anterior apprehension / Jobes relocation (young patient)

- ACJ assessment

- biceps assessment


- C spine




AP view (True AP)

- acromio-humeral interval:  Normal 1-1.5 cm, < 0.7cm abnormal

- sclerosis greater tuberosity / acromion

- lateral Acromion spur



Acromial Spur AP


Axillary Lateral

- os acromion

- bone scan to exclude symptomatic hypermobility


Os Acomionale Axillary Lateral Xray


Supraspinatus Outlet View

- Acromion morphology / calcification Coraco-Acromial Ligament

- scapula lateral variant

- plate on affected shoulder, other turned out of way 

- 10° caudal


Scapular Lateral for Acromial Morphology


Zanca view


- half voltage / centred on ACJ / 10o cephalad





- dynamic impingement

- bursitis


Shoulder Ultrasound Bursitis





- assess acromial morphology

- look for tendinosis / tears


MRI Type 3 Acromion




Non Operative


HCLA injection 



- decreases pain & inflammation

- diagnostic


Alvarez et al Am J Sports Med 2005

- RCT HCLA v LA in RC tendonosis

- no clinical difference between the two groups


Cuff Rehabilitation


Rockwood 3 Stages of Physio


1. Decrease Inflammation / Increase ROM

- rest

- gentle ROM 

- posterior capsular stretches

- scapula & trunk stabilisers

- modify activities



2. Cuff Stabilisation and Balancing

- strengthen humeral depressors

- work on SSC and IS

- takes load off SS

- theraband / IR / ER exercises

- avoid abduction drills


3. Deltoid strengthening

- task specific exercises


Operative Management






Believe primary problem is extrinsic impingement

- abnormal acromial morphology on outlet view

- spurs in CA ligament




Ketola et al JBJS Br 2009

- RCT of patients with impingement

- treated with exercise program or acromioplasty + exercise program

- no difference between the two groups


Henkus et al JBJS Br 2009

- RCT of bursectomy alone v bursectomy + acromioplasty

- no difference between the two groups


Open v Arthroscopic Acromioplasty




Sachhs JBJS 1997

- open v arthroscopic

- open longer return to work & in hospital stay

- results similar


Davis et al Am J Sports Med 2010

- meta-analysis of open v arthroscopic acromioplasty

- no significant difference in outcome

- longer return to work and inpatient stays

Open Acromioplasty

Described by Neer / modified by Rockwood


Two Step Acromioplasty


1.  Anterior acromioplasty

- resect anterior acromion back to ACJ

- prevent impingement in flexion


2.  Resect anteroinferior acromion 





- beach chair 

- mark anatomy

- limb draped free



- along anterolateral border acromion

- curve into anterolateral incision


Superficial Dissection 

- expose deltoid to ACJ

- find fibrous raphe at anterolateral corner acromion 

- marks anterior & middle parts of deltoid

- split raphe 3cm, ensure protect underlying cuff

- bursa is now exposed, separate subdeltoid space


Deep Dissection

- detach deltoid from anterior acromion to ACJ 

- release CA ligament 

- place retractor under acromion to protect cuff

- tablespoon, Langerhan's retractor turned on side


2 stage acromion resection with microsagittal saw

- anterior acromion level with ACJ

- antero-inferior acromion

- ensure surface smooth


Resect distal 2cm clavicle if OA

- < 4% of patients

- only if pain referable to ACJ 

- confirmed by LA preoperatively



- inspect cuff & repair defects

- abduct & rotate humerus

- biceps tenodesis if > 50% torn



- ? repair CA ligament

- reattach Deltoid No. 2 ethibond intraosseous sutures


Post Op

- rendulum exercises & passive flex

- sling for comfort

- no active abduction for 6/52 to protect deltoid




RC Tears

Arthoscopic Supraspinatous Repair


Large Supraspinatous TearSS tear arthroscopy GHJSS tear arthroscopy




Improved cosmesis

Shorter hospital stay / less immediate post operative pain

Deltoid not detached

Ability to evaluate and treat coexisting intra-articular pathology i.e. biceps




No quicker to rehab or return to activities 

- limiting factor is healing of tendon to bone

- healing rates not as high especially for large to massive tears

- steep learning curve / longer surgery




1.  Footprint

- 25 x 15 mm

- healing zone

- the greater the extent a repair covers, the greater the chance for tendon bone healing


2.  Suture technique


Note:  Most common means of failure is suture cutout


A.  Open transosseous



- performed in open surgery

- captures a wide section of cuff footpring

- very secure repair with uniform compression between cuff and bone


B.  Single row repair



- anchors placed in line laterally at insertion


C.  Double row repair



- medial anchor row at articular margin

- lateral anchor row at lateral footprint


Kim et al Am J Sports Med 2006

- biomechanical study

- more successful at restoring footprint

- less gap formation

- increased load to failure


D.  Transosseous equivalent / suture bridge



- biomechanically replicate tradional open transosseous

- sutures crossed as below in double row

- aiming to increase contact between cuff and footprint


Arthroscopic Suture Bridge Cuff Repair


Siskoksy et al AAOS 2007

- biomechanical study suture bridge v double row

- bridge higher load to failure

- no difference in gap formation




Outcome arthroscopic


Lafosse et al AA Should Elbow Surgeons 2006

- 105 patients treated with double row

- 11.45 structural failure on CT / MRI


Sugaya et al JBJS Am 2007

- prospective study 106 FT

- arthroscopic double row

- MRI follow up

- 17% retear

- 5 % small to medium

- 40% large and massive


Arthrocopy v mini-open


Kim et al Arthroscopy 2003

- arthroscopy v mini open

- similar outcomes in each group

- poor outcome related to size of tear, not method of repair


Verma et al Arthroscopy 2006

- arthroscopy v mini open

- US review

- 24% retear mini-open

- 25% retear arthroscopic

- no difference in outcome


Bishop et al AAOS 2004

- mini open v arthroscopic

- MRI review

- tears < 3 cm: 26% retear mini open, 16% arthroscopic

- tears > 3m: 38% v 76%

- do larger tears do better with open surgery?


Morse et al Am J Sports Med 2008

- meta-analysis of arthroscopic v open

- no difference in outcome or complications


Single v Double Row


Francheschi et al Am J Sports Med 2007

- RCT single v double row

- 60 patient

- no difference functional outcome

- improved cuff appearance on MRI


Burks et al Am J Sports Med 2009

- RCT single row v double row

- 20 in each group

- 1 retear in each group

- no difference in MRI appearance or clinical outcome




Churchill et al J Should Elbow Surg

- arthroscopic took average 10 minutes longer / cost $1000 dollars more

- even at high volume centres


Arthroscopic Supraspinatous Repair





- lateral decubitus with arm traction 10 lb or

- beachchair in Tmax / Spyder (can depress arm and ER to aid visualisation)

- water pump

- useful to have adrenalin in bags

- stable BP 110 (interscalene block can help)

- inject LA with A into subacromial space and prospective portals




Posterior Portal

- make more superior and lateral

- awkward for GHJ arthroscopy

- good visualisation in subacromial space

- will put camera over and high above tear


Lateral portal

- standard position

- insert large 8 mm cannula (will need to pass sutures)

- perform bursectomy +++ for visulisation

- bursa posteriorly and medially often bleeds

- perform SAD

- control bleeding with electrocautery and temporary increases in pump pressure


Anterior portal

- smaller 6 mm

- for suture shuttling




Prepare insertion

- debride tendon edges

- debride footprint to punctate bleeding


Arthroscopic Cuff TearArthroscopic Cuff Prepare InsertionArthroscopic Cuff Prepared Footprint


Assess tendon mobilisation / tear geometry

- perform releases if needed

- as per open surgery

- above and below tendon 1 cm medial to glenoid

- release coracohumeral ligament




Large U shaped tendon

- insert margin convergence sutures

- put camera in lateral portal

- insert posterior cannula over switching stick

- anterior and posterior bird beaks


Arthroscopic Cuff Repair Margin Convergance 1Arthroscopic Cuff Repair Margin Convergance 2


Place medial row anchors

- anterior first

- insert 18 G spinal needle and ensure good angle

- just medial to articular cartilage

- stab incision

- insert 5 mm anchor


RCR arthroscopic Spinal NeedleRCR Arthroscopic TapRCR Arthroscopic AnchorRCR Arthroscopic Anchor 2


Pass sutures in lateral margin cuff

- camera posterior

- elite / scorpion / concept suture passer via lateral portal

- pass sutures through cuff anterior to posterior

- retrieve sutures through anterior portal

- retrieve via anterior portal


Suture PassageSuture Retrieval


Repeat with posterior anchors


Large Cuff Repair 1Large Cuff Repair 2Large Cuff Repair 3


Tie sutures

- posterior to anterior / anterior to posterior


Double row

- either pass second lateral row of anchors or

- use foot print anchors, retrieve previous sutures

- can make suture bridge configuration

- check repair via lateral portal


Arthroscopic Supraspinatous RepairArthroscopic Cuff Suture Bridge RepairArthrscopic Cuff Repair






Full thickness tear (FTT)

- variable amount retraction from insertion


Rotator Cuff Tear Large


Partial thickness tear (PTT)

- incomplete

- bursal or articular sided


Articular sided tearBursal Tear




Older patients

- average age 60

- uncommon < 40

- cadavers  30%


Milgrom & Schaffer JBJS Am 1995

- rotator cuff changes In asymptomatic adults

- 50% at 50 years

- 80% at 80 years




Blood Supply


Proximal from muscle belly

- suprascapular artery

- subscapular artery


Distal from bone

- branch of anterior circumflex humeral


Vessels more abundant on bursal side than articular side




1.  Healing

- full thickness tears don't heal because of presence of synovial fluid


2.  Progression

- tears do not necessarily extend


3.  OA

- 5% FTT go on to cuff arthropathy if untreated




Chronic Tears

- 95% 

- abnormal tendon


Acute tears

- trauma 

- 5% 

- normal tendon




No evidence inflammation at tear site

- tendinosis / angiofibrotic dysplasia



- most common involves supraspinatus

- infraspinatus / T minor maybe torn

- subscapularis seldom torn




1.  Size 



- Small       < 1 cm

- Moderate  1-3 cm

- Large       3-5 cm

- Massive    > 5 cm


2.  Extent


Partial Thickness


Quite common

- patients present with pain, not weakness

- difficult to differentiate from impingement

- MRI with gadolinium


A.  Intra-tendinous

- in tendon

- no communication with bursa / joint


Supraspinatous Tendinosis MRISubscapularis TendinosisInfraspinatous Tendinosis


B.  Articular side

- most common

- blood supply poor

- healing decreased by synovial fluid 

- seen post traumatic in young

- probably due to intrinsic causes in elderly


Supraspinatous articular sided tear


C.  Bursal side

- on subacromial surface

- less common

- likely to be secondary to impingement


Full Thickness


One tendon 

- supraspinatus only


Multiple Tendons 

- more likely OA if multiple tendons involved


3.  Topography


Sagittal Plane


Superior - SS alone

Anterosuperior - SS & SSC

Posterosuperior - SS & IS

Total cuff - All 3 tendons


Coronal Plane


A. Minimal retraction

- close to insertion


Supraspinatous Tear Minimal Retraction


B. Moderate retraction

- humeral head


Supraspinatous Tear Moderate Retraction 1Supraspinatous Tear Moderate Retraction 2


C.  Significant retraction

- at glenoid


Supraspinatous Tear Retraction to GlenoidSupraspinatous Tear Retracted to Glenoid T1







- 2° to tear

- can be limited by pain

- can use LA to differentiate


History of injury, especially dislocation

- minimal pre-injury symptoms

- suggests acute tear of normal tendon


Chronic Tear 95%

-  long history impingement

-  no history of injury




SS IS Clinical Photo 1SS IS Clinical Photo 2



- supraspinatus & infraspinatus

- rapid wasting with acute tears

- gradual wasting with chronic tears


Weakness related to

- size of lesion

- amount of pain

- grade 3 (MRC) or less indicates large tear




1.  Patient's arm held elevated at 90°

- arm in 30° forward flexion with thumb down

- test resistance to inferior pressure

- palpate


2.  Drop arm sign

- passively abduct arm

- get them to put it back to their side slowly

- apply small amount of pressure

- will drop arm at 30o


3.  Shoulder hiking

- usually means massive cuff tear


Shoulder Hiking




1.  Resisted ER


2.  Lag

- put in arm in maximum ER

- ask patient to hold that position and release arm

- unable to maintain ER / arm lags


3.  Hornblowers

- abduct and ER arm

- arm drops as unable to maintain ER

- Teres minor


Involvement of IS can often indicate a large or massive tear




1.  Gerber lift-off test

- IR hand to back pocket

- patient should be able to maintain hand away from bottom if SSC intact

- need sufficient IR for this test

- otherwise need belly press test


2.  Belly press test

- fists on belly

- elbows forward / to eliminate deltoid

- resist force lifting fists away from belly


3. Increased ER compared with other arm


Subscapularis tear increased ER




Improves pain and allows physio



- ensures pain from shoulder pathology




Views as for impingement

- assess acromion / GHJ OA / high riding head





- non invasive

- cost effective

- dynamic image

- can be used in orthopedic office

- useful and simple for assessment of cuff integrity post surgery



- user dependant

- accuracy increases with skill and experience

- may miss small tears / partial thickness tears

- still images not easily interpreted by surgeon (c.f. MRI)




O de Jesus Am J Roentengology meta-analysis MRI v MRA v US

- MRA most accurate

- MRI and US comparable




Shoulder Ultrasound Normal SupraspinatousShoulder Ultrasound Infraspinatous NormalShoulder Ultrasound Subscapularis Normal




Shoulder Ultrasound Supraspinatous Tear




Arthrogram Intact RC




Look for

- SS / IS / SSC / biceps

- PT v FT

- size of tear

- retraction

- atrophy / fatty infiltration 


Shoulder MRI Supraspinatous Fatty Infiltration


Partial thickness tears 

- best seen on T1 with gadolinium 

- see if communicates from GHJ to SA space


For more MRI see

- massive tears

- partial thickness tears

- full thickness tear




Gold Standard

- assess for partial articular tears in GHJ

- assess for bursal sided tears in subacromial space


Management Guidelines


1. Repair all acute full thickness tears


2 Repair chronic full thickness tears

- young patients

- after failure non operative management

- with disability 2° weakness or pain


3. Observe chronic tears with no disability

- especially in elderly


Non-operative Management


As per impingement

- satisfactory outcome in 50%

- no symptoms of pain or weakness

- both PT and FT tears




Full Thickness Tears

Surgical Options


1.  Open antero-lateral approach 


Large / Massive Cuff Tear


2.  Deltopectoral approach


Large Subscapularis tear


3.  Arthroscopic Assisted Mini-open



- Small / Moderate Cuff Tear < 3cm

- no retraction



- arthroscopic SAD

- assess tear with scope

- repair RC through deltoid split



- avoids deltoid detachment from acromion

- small scar

- still have to immobilise shoulder for 6/52 to protect cuff tear


4.  Arthroscopic repair




Gartsman et al J Should Elbow surgery 2004

- prospective randomised trial

- no large tears, no previous surgery

- all arthroscopic single tendon repair, all type 2 acromion

- no difference in functional outcome whether had SAD or not


Advantages of performing SAD

- long history of successful use

- minimal complications

- aids visualisation in open and arthroscopic repairs


Biceps / SLAP


Franchesci et al Am J Sports Med 2008

- RCT 63 patients with RC tear and SLAP 2

- repair v tenotomy

- significantly better shoulder scores and ROM in tenotomy group




4 types of cuff tears


1.  Cresent shaped

- simple lateral repair


Supraspinatous tear Cresent ShapedSupraspinatous Tear Crescent Shaped


2.  U shaped

- larger

- need margin convergence, then lateral repair


Supraspinatous Tear U shaped


3.  L shaped


Tear of Suprapinatous laterally

- transverse extension

- at rotator interval anteriorly

- or in supraspinatous posteriorly


4.  Massive


Rotator cuff retracted to glenoid


1.  Open Rotator Cuff Repair



- large to massive tear



- deltoid taken off anterior acromion

- acromioplasty with saw

- bursectomy for exposure

- margin convergence if large tear

- suture anchor repair laterally

- single / double row / suture bridge configuration

- deltoid repaired via intra-osseous sutures



- reliable

- good results in terms of tendon healing and outcome



- longer, more painful recovery

- must protect deltoid repair 6/52

- no early mobilisation

- risk of deltoid dehiscence

- miss any intra-articular pathology if don't perform arthroscopy

- ? management of biceps





- lazy beachchair



- Neer type  

- over ACJ and anterior clavicle

- angle down between anterior and middle deltoid



- down to deltoid

- identify raphae between anterior and middle deltoid

- carefully open interval

- must no damage any underlying cuff / LHB

- must not extend incision > 5 cm from acromion or risk damaging anterior AXN

- take deltoid off anterior acromion with diathermy

- control acromial branch of the thoracoacromial artery



- Neer style 2 saw cuts

- take anterior acromion in line with anterior clavicle

- second cut takes angle of acromion superior to inferior

- make more generous in large to massive tear for exposure




Tear completely identified

- Edges trimmed

- Digital stripping of upper & lower surfaces from scar

- Mornihans retractors / Mason-Allen suture to grasp tendon

- assess tear geometry

- assess ability to repair to footprint


Techiques to mobiise retracted SS tendon


1.  Release CHL (runs from coracoid to free edge SS / into rotator interval)

2.  Release RC interval

3.  Mobilise above and below supraspinatous tendon

4.  Release above glenoid 1.5cm (beware suprascapular nerve)

5.  Interval slide - divide between SS and IS posteriorly, rotator interval anteriorly

6.  Medialise insertion - take away some of articular cartilage

7.  Repair SSC and IS for restoration of force couplet (if SS irrepairable)


Repair Options


1.  Direct suture of tendon

- margin convergence


2.  Suture of tendon to bone


A.  Anchors

- roughen footprint

- 1 or 2 row technique

- medial row downwards pressure

- lateral row pulls across


Shoulder Open Rotator Cuff Repair APShoulder Open Rotator Cuff Repair Lateral


B.  Trough made in bone

- in anatomical neck near GT

- drill-holes made in trough

- tendon sutured through drill-holes / anchors


C.  Intraosseous sutures

- suture passer

- tie over small poly plate (arthrex)


3.  Mc Laughlin Technique

- if direct suturing unfeasible

- Y closure performed

- tendon defect made triangular with base at insertion

- apex closed as far as possible with shoelace suture

- unclosed tendon edges sutured to cancellous bone of humeral head


Repair done with arm by side

- may be abduct to aid repair

- should be able to be brought by side at completion

- may need abduction pillow



- intra-osseous deltoid repair

- no 1 ethibond

- careful attention to this part of surgery


Large - Massive Tear 


Generous acromioplasty 

Excise distal clavicle for better exposure

Techniques as above


Post op


Must protect deltoid repair

- passive ROM 6/52, hand and elbow exercises, sling

- active ROM begin at 6/52

- strengthening at 3/12

- return to sport after 6/12


Poor prognosis

- large-massive tear

- fatty infiltration / atrophy

- older patient (>60)

- poor subacromial decompression

- excessive acromial resection

- damage to Deltoid

- improper rehabilitation

- smokers & DM


2.  Arthroscopic SAD + Mini open Rotator Cuff Repair



- perform subacromial decompression with arthroscope

- no need to detach deltoid

- made 2 - 5 cm deltoid split directly over tear and repair



- moderate size tear up to 3 cm



- posterior portal for camera

- lateral portal for SAD

- localise tear with needle

- make mini open incision over tear

- repair as above




Open v Mini-open


Mohtadi et al Am J Sports Med 2008

- RCT open v mini-open

- massive tears excluded

- mini open better shoulder scores at 3/12

- no difference at 1 or 2 years


Tear integrity


Papadopolous et al J Should Elbow Surg 2011

- ultrasound evaluation of tears at 3 years in 37 mini-open patients

- 48% intact in patients who tended to have smaller original tears and be 15 years younger

- most patients had satisfactory outcome





- up to 50%

- increased in older patients with larger tears


Cuff Arthropathy 

- 5% massive rotator cuff tears

- associated with rerupture

- high riding humeral head


Shoulder High RIding Humersu





- inadequate acromioplasty

- rerupture

- wrong diagnosis (frozen shoulder / cervical radiculopathy)


Difficulty using arm above shoulder height

- rupture of repair of FT tear

- deltoid detachment or denervation

- biceps tendon rupture




Deltoid avulsion


Axillary nerve injury


Acromial fracture


RC Tear / Anchor Pullout


Rotator Cuff Anchor Pull Out


Massive Tears

DefinitionsMassive RC Tear High Riding Humeral Head MRI


Massive tear 


1.  > 5cm 

- retracted to humerus / glenoid margin


2.  At least 2 complete tendons

- lose SS / IS or SS / SC





- SS + SSC


Postero-Superior defects

- SS + IS
- more common




Cuff works to compress / depress head in glenoid while deltoid acts as prime mover

- ff still have intact force couple often good function


Plan is to reproduce force couple 

- if tear is below equator of head 

- get uncoupling of cuff force couple

- lose cuff depressor effect & acts as head elevator


Integrity of coracoacromial arch integral component of repair

- acts as check rein to proximal migration 




Massive SS / IS wasting + rupture LHB

- weakness

- reduced active ROM

- atrophy


Shoulder Hiking due to massive cuff tearSupraspinatous and Infraspinatous wasting


2 classic signs


1.  ER lag sign


2.  Hornblowers

- 100% sensitive, 93% specific


Both indicate infraspinatous is torn which is usually a sign of a massive PS tear




Suprascapular nerve palsy

Brachial plexus injury

Cervical stenosis




Reduced acromiohumeral space

- < 7 mm RC tear

- < 5 mm massive tear


Rotator cuff OA

- acetabularisation


Decreased Acromioclavicular DistanceShoulder Massive Rotator Cuff Tear CTMassive Rotator Cuff Tear




1.  Level of retraction

- past coracoid irreparable


MRI Supraspinatous Retracted to Glenoid Margin


2.  Quantify fatty infiltration Goutallier


Parasagittal MRI T1

- atrophy and fatty replacement in SS / IS fossa


0 - no fat

1 - minimal fat

2 - more muscle than fat


Supraspinatous fatty infiltration grade 2


3 - fat equal muscle


MRI Fatty Infiltration Supraspinatous Infraspinatous


4 - more fat than muscle


Grade 4 Fatty Atrophy


3 & 4 have poor prognosis

- poor functional improvement with repair

- high incidence of retear


3.  Atrophy


Also poor prognosis


MRI Supraspinatous Atrophy




Non Operative


Physio /  HCLA

- improvement in 50-85%






A.  Primary repair / Debridement

1.  Mobilisation and repair

2.  Partial repair

3.  Decompression and debride

4.  Suprascapular nerve release


B.  Salvage

1.  Local tendon transfer - SSC

2.  Distant tendon transfer - P. major / Lat dorsi

3.  Allograft

4.  Synthetic Graft

5.  Arthroplasty


Repair / Debridement


1.  Rotator Cuff Mobilisation and repair


Technique of mobilisation

- release coracohumeral ligament

- anterior slide (between SS and SSC)

- posterior slide (between SS and IS)

- release above glenoid 1 cm

- medialise insertion

- transosseous repair




Bigliani et al J Should Elbow Surg 1992

- 61 patients massive cuff tears followed up 7 years

- open repair

- 50% excellent and 30% good


2.  Partial repair



- restore balanced force couplet

- SSC + partial SS / IS repair

- act in conjuction to depress humeral head

- allow deltoid to work


Massive Cuff TearMassive Cuff Tear Partial Repair 1Massive Cuff Tear Partial Repair 2


Massive Cuff Repair Partial Repair 3Massive Cuff Tear Partial Repair 4Massive Cuff Tear Partial Repair 5




Rhee et al Am J Sports Med 2008

- partial repair with interposition of biceps tendon to bridge gap

- MRI of 14 / 16 cases done arthroscopically

- complete healing in 60%


3. Decompress & debride alone



- doesn't restore power

- aiming for pain relief in elderly population



- maintain Coracoacromial arch to prevent humeral head escape

- don't perfrom SAD to preserve CA ligament

- debride cuff edges

- debride GT / tuberoplasty to decrease impingement

- biceps tenotomy / tenodesis




Boileau et al JBJS Am 2007

- demonstrated good results with tenotomy or tenodesis

- 61 patients with irreparable tears


Liem et al Arthroscopy 2008

- 31 patients average age 70

- debridement cuff edges + biceps tenotomy

- no SAD

- reasonable results


Walch et al Arthroscopy 2005

- arthroscopic tenotomy in 307 irreparable RC tears

- 87% satisfied with results


4.  Suprascapular nerve release



- retraction of cuff tethers / impinges SSN

- release of nerve arthroscopically relieves pain



- arthroscopic release

- see miscellaneous/suprascapular nerve for technique




Indications for tendon transfer / Graft


Young patient with poor function

- failed primary repair

- significant weakness

- good deltoid function

- CA arch intact / no superior escape

- good ROM

- either posterosuperior or anterosuperior defect


1.  Subscapularis Transfer



- may lose humeral depressor effect

- lose abduction with deltoid



- release upper 1/3 tendon from capsule




Karas et al JBJS Am 1996

- 20 patients

- good results in 17


2.  P.  Major Transfer



- functional deficit from SSC tear



- deltopectoral approach

- use sternal head rerouted under clavicular head for better line of pull




Jost et al JBJS Am 2003

- reasonable results in isolated SSC

- less so with combined SS and SSC (doesn't recommend)


3.  Lat Dorsii Transfer



- IS / SS tear




Lateral Decubitus position

- arm over mayo table


Standard deltoid splitting open approach to subacromial space

- acromioplasty - minimal, preserve CA arch

- ACJ excision if needed

- tag cuff edges medially with sutures to augment repair

- place lateral anchors / sutures


L shaped incision

- inferior margin deltoid, lateral aspect of latissimus dorsi

- arm forward flexed to 90 degrees and IR

- infraspinatous usually very wasted

- identify T major

- find L dorsi below T major, develop interval between the two

- identify tendon insertion on humerus, often have to release T major tendon from it

- place homan over humeral head

- release tendon from insertion / keep long

- is usually thin / 3 cm wide / 5 cm long

- suture each margin with strong suture, leave limbs long to pass tendon

- release muscle belly for length / above and below / must identify and preserve pedicle

- tunnel tendon under deltoid & acromion

- suture anchors repair to GT + subscapularis + medial cuff remnant

- repair with arm in abduction and ER

- maintain in abduction and external rotation splint for 6/52


LDTT exposureLDTT intervalLDTT find tendon


LDTT homanLDTT tendonLDTT tendon suture


LDTT ReleaseLDTT humeral headLDTT repair


Pre op Lat Dorsi TransferPost Op Lat Dorsi TransferLat Dorsi Transfer Lateral




Miniacci JBJS Am 1999

- 14 / 17 good results regarding pain relief and ROM


Tauber et al JBJS Am 2010

- compared patients with tendon transfer to those with tendon + bone block

- significantly improved results in bone block

- 4/22 reruptured on MRI in tendon v 0/20 in bone block group


4.  Allograft




Moore et al Am J Sports Med 2006

- 28 patients average age 59

- patella tendon or achilles

- sewn to tendon medially

- bone block laterally or sutured

- 15 repeat MRI - all complete failure of graft

- 1 infection and 1 allograft rejection

- similar functional results to debridement alone

- not recommended by authors


5.  Synthetic Allograft




Nada et al JBJS Br 2010

- dacron graft for massive cuff tears in 17 patients

- sutured medially, tied through bony tunnels laterally

- 90% satisfaction

- 15/17 intact on MRI

- 1 rupture, 1 deep infection


6. Arthroplasty


CTA Hemiarthroplasty / Reverse TSR

- salvage in patients > 65 years


Partial Thickness Tears



Pain & Stiffness

- often more pain than FT tears


Bursal side tears more painful than articular


Articular side more common


May see in young patient overhead throwing




Painful arc


Impingement signs


No weakness

- function good

- cable system intact




Articular sided more common than bursal



- A (articular)

- B (Bursal)


Grade 1    <  3mm

Grade 2    <  3-6 mm

Grade 3    <  6 mm footprint exposed




Sher et al JBJS Am 1995

- 19 - 39 years - 4% PT , no FT

- > 60 years - 26% PT, 28% FT




Yamanaka et al Clin Orthop 1994

- 40 patients with articular sided PT

- a few heal 10%

- a few don't progress 10%

- 50% enlarge

- 30% become FT




Articular Sided


Shoulder MRI Footprint Exposure Supraspinatous Articular TearShoulder MRI Articular Supraspinatous Tear


Bursal Sided




Articular side




Rotator Cuff Small Partial Articular TearPartial Articular Supraspinatous Tear



- see uncovering of footprint

- SS inserts laterally

- bare area lateral to cartilage


PASAT Arthroscopy 1PASTA Arthroscopy 2


Bursal Sided


Shoulder Scope Bursal Supraspinatous TearSupraspinatous Bursal Sided Tear




Non Operative


Physio / HCLA






1.  Failure of non operative treatment (6-12 months)

2.  Symptomatic pain or weakness

3.  Repair if > 50% depth




1.  Acromioplasty and debridement

2.  Conversion to FT and repair

3.  Repair without conversion to FT


1.  Acromioplasty + debridement



- < 50% tears


Shoulder Scope PASTA Debridement




Park et al Orthopaedics 2003

- 37 patients PT < 50%

- 87% good results at 2 years


Weber Arthroscopy 1999

- 63 patients with grade 3A / 3B

- mini open repair v acromioplasty / debridement

- significantly improved results with repair


Cordasco et al Am J Sports Med 2002

- SAD and debridement

- 2A 5% failure rate

- 2B 38% failure rate

- recommend repair 2B PT



- bursal sided tears tend to do more poorly than articular sided

- repair > 50% especially in young patients


2.  Acromioplasty and repair


May be done open / arthroscopically / arthroscopically + mini open



A. Convert to FT and repair

- arthroscopic or open

B. Transtendinous articular repair

- must be done arthroscopically

C.  Bursal repair

- can be done arthroscopically or open


A.  Convert to FT and repair


Kamath et al JBJS Am 2009

- 42 > 50% PT converted to FT arthroscopically

- 88% cuff intact on US

- 93% patient satisfaction


B.  Articular sided / transtendinous PASTA repair


Gonzalez J Shoulder Elbow Surg 2008

- biomechanical study of PT articular

- coversion to FT and double row repair v

- transtendinous repair of PT

- transtendinous repair higher ultimate strength and

- decreased gap formation


Ide et al Am J Sports Med 2005

- all arthroscopic transtendinous repair 3A PT

- 14 / 17 excellent, 2 good, 1 fair


C.  Bursal sided

- can repair top layer of tear only


Technique Transtendinous Arthroscopic PASTA Repair 



- repair medial footprint

- don't injure intact tendon

- can range immediately

- in fact need to do so to avoid stiffness




Camera in glenohumeral joint

- anterior glenohumeral cannula for suture management

- 5mm anchor passed through SS transtendinous into footprint

- retrieve sutures through anterior GH portal


Shoulder Partial Articular Supraspinatous Tear PASTA


Must pass sutures from anchor through torn cuff

- aim to reapproximate to footprint


A.  Pass bird beak suture passers through cuff to retrieve sutures


B.  Pass 20G spinal needle and pass down 0 nylon, retrieve via anterior portal

- tie to thread, and pass suture back through tendon

- do so each time for each thread in horizontal mattress pattern


Shoulder PASTA Repair Needle Suture ShuttleShoulder PASTA Repair Sutures Shuttled


Camera into subacromial space

- lateral portal

- retrieve sutures and tie

- check repair again via GHJ


Shoulder PASTA Repair Sutures in Subacromial SpaceShoulder PASTA Repair Knots Tied Subacromial Space


Post op

- can range aggressively

- the repair is protected by the intact portion of the tendon

- prevents stiffness


Technique Open Articular PT Tears



- put spinal needle through torn portion

- pass suture through to mark tendon


Open approach over needle entry

- identify tear by suture

- convert to FT and repair


Technique Arthroscopic Bursal Sided Tear


Identify tear

- see partial uncovering footprint

- camera in subacromial space

- debride tear edges

- prepare footprint insertion


Insert anchor

- pass sutures through top layer of torn tendon

- tie down


Bursal Sided Supraspinatous TearBursal Sided Supraspinatous Tear Repair

Revision Cuff Tears




- may be up to 50% retear over time

- many asymptomatic




Shoulder MRI Failed Rotator Cuff RepairShoulder MRI Failed RC Repair 2




1.  Debride / Biceps tenotomy or tenodesis


2.  Revision cuff repair

- open

- arthroscopic


Revision Rotator Cuff 1Revision Rotator Cuff Repair 2


3.  Tendon transfer







Subscapularis Arthroscopic Repair


- extra-articular



- posterior portal very lateral so can see anterior aspect subacromial space

- port of Wilminton at anterolateral acromion to access SSC

- anterior portal in normal position, slightly more lateral so becomes working portal


SSC Repair Portals 1SSC Repair Portals 2



- identify tendon

- work through portal Wilmington

- grasp, forms comma sign

- perform biceps tenodesis

- tag SSC with fibrewire


SSC tornSSC comma sign


Subacromial space

- place standard lateral portal as well

- total bursectomy plus acromioplasty

- use tagging sutures to identify SSC

- release as necessary

- may need long posterior cannula to see anteriorly

- may need to move camera to lateral portal to see around corner anteriorly

- can use 70 degree scope


SSC Tagging Suture Subacromial SpaceSSC Debridement Anterior Subacromial


Prepare footprint

- debride

- insert anchors (retract port of Wilminton into subacromial space)

- pass sutures with suture passer

- tie


SSC Debride FootprintSSC First AnchorSSC Suture Passage


SSC Second AnchorSSC Repair





Subscapularis Tears

AnatomySSC Longitudinal Tear


Largest and most powerful rotator cuff

- arises coastal border of scapula

- superior 2/3 tendon inserts into LT

- inferior 1/3 inserts into proximal humerus



- IR (with T major, P major, Lat Dorsi)

- part of force couplet depressing humeral head




Can be isolated event


More commonly seen with SS tears (2% in MRI study)

- anterosuperior tears




- biceps subluxation

- coracoid impingement





- hyperextension and ER






Pain anterior shoulder


Increased ER


Lift off test


Belly Press

- elbow falls posteriorly to harvest post deltoid




Subscapularis Tear MRISubscapularis FT Tear MRI Glenoid RetractionMRI Retracted Subscapularis TearMRI SSC tear minimal retraction




Complete absence of SSC


Subscapularis Retracted Tear Arthroscopy


Comma Sign


SSC tornSSC Comma Sign


Medially Subluxed Biceps


Medially Subluxed Biceps




Operative Indications



- failure of 6/12 non operative



- fix acutely



1.  Debridement

2.  Open Repair

3.  Arthroscopic Repair






Edwards et al Arthroscopy 2006

- 11 patients with SSC tears

- debridement

- tenotomy in 9 with dislocating / unstable biceps

- 9/11 good results


Open Repair




Deltopectoral approach

- preserve axillary nerve inferiorly

- mobilise SSC

- subscapular nerves on anterior surface medial to glenoid rim

- tenodesis LHB

- suture anchor repair to lesser tuberosity




Barti et al Am J Sports Med 2010

- 30 traumatic tears, patient average age 43

- associated biceps subluxation and HAGL's seen

- repair structurally intact in 93%

- 20% still unable to perform lift off / belly press tests

- these patients had higher degree of fatty infiltration preoperatively


Arthroscopic Repair


Intra-articular technique

- camera in GHJ

- anterosuperior portal

- mobilise tendon front and back

- must remove adhesions

- roughen insertion point on LT / gentle with burr as bone is soft

- insert twinfix anchors x 2 via stab incision

- pass birdsbeak suture passer through portal and through SSC

- retrieve 3 sutures through tendon

- retrieve 4th suture over top of SSC


Extra-articular Technique

- see article




Lafosse et al JBJS Am 2007

- isolated repair in 17 patients

- 15 intact repairs and 2 partial reruptures on CT arthrogram

- good outcomes


Late reconstruction


P. major transfer




Jost et al JBJS Am 2003

- good results in isolated SSC tears

- results poor in shoulder arthroplasty