Locked Glenohumeral Dislocation

Definition

 

A GH dislocation which has been missed for a significant period of time

- time period is arbitary

- > 3-6 weeks

 

Pathology

 

Humerus soft and osteoporotic

Significant soft tissue contractures

 

1.  Anterior / subcoracoid dislocation

 

Beware

- scarring to NV structures

- RC tears including SSC, especially > 40

- anterior glenoid wear / can have significant bone loss

- large engaging Hill Sachs / humeral head defects

 

2.  Posterior dislocation

- posterior glenoid wear

- reverse Hill Sach's / large anteromedial defects

 

Epidemiology

 

Anterior 41%

 

Posterior 59%

 

Aetiology

 

Multi trauma

Seizures

Poor patient mental function

 

History

 

Limitation ROM

History multi trauma / seizures

Previous treatment

- often have had inadequate X-rays

- extensive physiotherapy / injections

 

Examination

 

Usually some asymmetry

 

Some reduction ROM

 

Palpate humeral head anteriorly / posteriorly

 

X-rays

 

Scapular AP view

Scapular lateral

Axillary lateral

 

CT

 

Aids diagnosis and preoperative planning

 

Management

 

Non Operative

 

Indications

- elderly 

- minimal functional limitation

- significant medical issues

 

Only operate if significant clinical problems

- anterior more difficult than posterior to solve

 

Operative

 

Closed reduction

 

Issues

 

1.  Timing 

- has been successful up to 6-8 weeks

- most successful outcomes in literature < 4 weeks

 

2.  Humeral head impression

- if this is locked on glenoid, closed reduction is contraindicated

 

3.  May be unstable afterwards

- need further open procedure

- need careful postoperative monitoring

- regular xray surveillance

 

Chronic Anterior Dislocation

 

1.  Large Humeral Head Defect

 

Hill Sach's

- posterolateral defect

- manage according to size

 

Defect < 40%

 

A.  Elevate and Bone graft defect

- < 4 weeks in young patient

- adequate bone, salvageable cartilage

- posterior approach

- split deltoid / L shaped Infraspinatous tenotomy

 

B. Advance Infraspinatous +/- GT

- posterior approach

- < 20% IS alone

- if larger must also take GT

 

Defect > 40%

 

A.  Allograft

- young patient

- pre-op CT to estimate humeral head size

- appropriate sized femoral / humeral head

 

B.  Prosthesis

- often significant OA with long standing dislocation

- anterior glenoid deficiency

- older patient

- increase retroversion of humeral component

- may need to address anterior glenoid deficiency

 

2.  Glenoid Deficiencies

 

Indicated when > 20-25% anterior glenoid eroded

 

Bristow / Latarjet

 

Glenoid Reconstruction

- humeral head

- iliac crest

 

 

3.  Soft tissue deficiencies 

 

Always combine with anterior labral repair +/- inferior capsular shift

 

4.  Rotator cuff tears

 

Significant issue

- if massive cuff tear, may lead to chronic instability

- very difficult to treat

 

CASE 1

 

50 year old, missed locked anterior dislocation one year

- head severely mis-shapen

- missing 50% glenoid

- massive rotator cuff tear

 

Treatment

- open reduction

- shoulder hemiarthroplasty / humeral head used to bone graft glenoid / rotator cuff repair

- unfortunately rotator cuff repair failed, and developed recurrent instability

- option: Reverse TSR / fusion

 

 

 

 

CASE 2

 

26 year old female

- ligamentous laxity, but no previous shoulder problems

- traumatic anterior shoulder dislocation

- leading to recurrent anterior subluxation

- had an arthroscopic anterior and posterior capsular plication

- shoulder now permanently dislocated anteriorly

- options: open posterior capsular release and latarjet / or fusion

 

 

 

Chronic Posterior Dislocations

 

Approach

 

Standard DP approach

- manage SSC depending on operative plan for humeral head defect

- open capsule

- remove any fibrous tissue in glenoid

- use lever to reduce humeral head

- usually can ignore posterior capsular detachments

 

Manage humeral head / glenoid defects

 

See Posterior Shoulder Instability

 

1.  Humeral Head defects

 

Posterior dislocation

- anteromedial

 

Defects < 40%

 

A.  Disimpaction and bone graft

- < 4 weeks, young patient

- articular cartilage must be salvageable

- via anterior approach

 

B.  McLaughlin

- < 20%, SSC only

- < 40% transfer SSC + LT into defect

- secure with 2 x cancellous screws

 

Defects > 40%

 

A. Allograft

- young patient

 

B.  Hemiarthroplasty / TSR

 

2.  Posterior Glenoid Deficiency

 

May need posterior bone graft