AVN Shoulder

Shoulder AVN

 

Epidemiology

 

Much less common than hip OA

- usually presents late

 

Aetiology

 

Similar causes as hip (AS IT GRIPS 3C)

 

Alcohol / Steroid / Trauma / Idiopathic

 

Gauchers

 

RA / RTx

 

Sickle Cell 

- commonest cause worldwide

- bilateral

 

Caisons / Chemotherapy

 

Blood Supply

 

Gerber JBJSA 1990

 

1.  Anterior Circumflex Humeral Artery

- primary blood supply

- becomes arcuate artery

- runs lateral aspect bicipital groove

 

2.  Posterior Circumflex Humeral Artery

- collateral circulation

- supplies head when GT / LT fracture

 

3.  Via Rotator Cuff

 

Fracture

 

Wide range of AVN after 4 part fractures

- about 1/3

 

Recent studies to explain this

 

1.   Suggest 2nd anastomotic system 

- via posteromedial branches of PCHA along inferomedial capsule

- blood supply may be further compromised by large exposure in ORIF

 

2.  Creeping substitution

- occurs more extensively in humeral head

 

3.  Rich vascular tissue surrounding humeral head

 

Natural History

 

Variable

- Difficult to predict

- Somewhat related to aetiology

- Sickle cell disease tend not to progress to arthroplasty

- Steroid induced far more likely

 

Less severe than femoral

- non weight bearing

- less conforming joint

- scapulothoracic motion

 

Pathology 

 

Superior head collapse at 90° mark 

- area of peak contact stress in abduction

- ROM Maintained until late

- Glenoid rarely affected

- Soft tissue and SSC rarely contracted

 

Classification / Cruess modification of Ficat-Arlet 

 

Stage 1

- prexray change

- only seen with MRI

 

Stage 2

- sclerotic changes in superior central head

- sphericity maintained

 

Humeral AVN Stage 2Humeral AVN Stage 2 MRI

 

Stage 3 

- "Crescent" Sign

- mild flattening articular surface

 

Shoulder AVN Stage 3

 

Stage 4

- significant humeral collapse with loss integrity joint surface

- loose bodies

 

Shoulder AVN Stage 4Shoulder AVN Stage 4

 

Stage 5

- degeneration extends to involve glenoid

 

AVN Shoulder Xray

 

Symptoms

 

Pain is major problem

- pain before significant loss ROM

- difficulty sleeping

 

MRI

 

Shoulder AVN MRIShoulder AVN MRI Sagittal

 

Management

 

Remove insult

- corticosteroids, alcohol

 

Non Operative

 

Maintain current shoulder ROM / Halt Progression

 

A.  Prevent disuse related stiffness

- passive physio

 

B.  Limit overhead activities

- Joint Reaction Force greatest > 90o

 

C.  Bisphosphonates

 

Operative

 

Core Decompression

 

Decrease intraosseous pressure & increase blood flow

- moderate success mainly in stage 1 or 2

 

Hemiarthroplasty 

 

Usually works well

- glenoid not usually affected

- Soft tissue and subscapularis rarely contracted 

 

Smith et al J Should Elbow Surg 2008

- steroid induced AVN

- survival 92% 10 year

- 2 patients needed revision for painful glenoid arthrosis

- good option

 

TSR

 

Indicated in stage V only

- beware in young patient < 65