POSTERIOR GLENO-HUMERAL INSTABILITY

INTRODUCTION

2-12% of all shoulder instability Isolation / MDI Symptoms are usually mild and can

be overlooked Athletes

ETIOLOGY

Congenital- Ligamentous laxity- Scapulohumeral anatomy

Acquired- Athletes- Repetitive stress to the posterior capsule resulting in laxity

 Traumatic- Fall or blow to arm in “at risk” position

(forward flexion, abduction and internal rotation)

 

ASSOCIATED ATHLETIC ACTIVITIES

ACTIVITY MOTIONWeightlifting Bench press,

push-upsPitching Follow-through phaseSwimming Butterfly and

freestyleRacquet sports Backhand stokesGolf Motions of lead armGymnastics Parallel bars, ringsBoxing Axial load with punching

CLASSIFICATION Voluntary /Involuntary Habitual Instability

Results from underlying neuromuscular imbalance Underlying psychiatric problems common Often refractory to surgery

Positional Dislocator Demonstrate instability by placing the arm in a position

of risk Usually do not have psychiatric illness or secondary

gain Ordinary avoid provocative manoeuvres Physiotherapy still first-line treatment but surgery gives

good results

CLINICAL PRESENTATION

Pain rather than instability Usually mild Occur during or after activity Traumatic event may precede onset

of symptoms Rarely is there a history of frank

posterior dislocation Slip, pop or click out and in

EXAMINATION - 1

Posterior joint line tenderness ROM - Normal Rotator cuff strength - Normal Scapular winging

secondary to scapula muscle dysfunction

Ligamentous laxity? Examine unaffected shoulder

EXAMINATION - 2 Load and Shift Test (posterior drawer)

Examiner grasps humeral head and pulls directly backward with the shoulder muscles relaxed.

Humeral head subluxates posteriorly (<50% normal)

Patients reaction to translation more important than amount

Posterior Apprehension Uncommon Arm brought into forward flexion and internal

rotation with posterior stress applied Sense of instability, pain or painful subluxation

is suggestive of the diagnosis

INVESTIGATIONS Shoulder XR

AP in ER/IR Lateral Axillary view Dynamic XR with shoulder subluxed

CT Arthrogram MRI

Labral changes Capsular Damage

EUA +/- arthroscopy Doubt regarding direction or extent of instability

MANAGEMENT

NON-SURGICAL TREATMENT

SURGICAL TREATMENT ARTHROSCOPIC OPEN

SURGERY - 1

INDICATIONS Recurrent, symptomatic,

unidirectional subluxation that has failed to respond to a comprehensive non-operative program

Posterior instability itself is not an indication for surgery 2/3 will respond to a proper exercise

program No patient who has not had 6/12 of an

exercise program should have surgery

SURGERY - 2

CONTRA-INDICATIONS Psychiatric disorder Significant degenerative gleno-humeral

arthritis Failure to undergo or co-operate in

physiotherapy program

Ligamentous laxity Multidirectional instability

ARTHROSCOPY

 Capsular shift 25% recurrence at 2 year follow-up in

one study on 20 patients  Capsulo-labral augmentation

41 patients in study – 86% improved stability

Thermal capsulorrhaphy Thin posterior capsule which is less

responsive to shrinkage Complicated by necrosis

SURGICAL PROCEDURES OPEN

SOFT TISSUE BONEPosterior capsulorrhaphy Glenoid osteotomyInferior capsular shift Posterior bone block(anterior/posterior)Infraspinatus advancementPosterior Bankart repairStaple capsulorrphaphyBiceps tendon transferSubscapularis transfer ARTHROSCOPICPosterior Capsulolabral AugmentationPosteroinferior Capsular ShiftThermal Capsulorrhaphy

OPEN TECHNIQUES - 1

Soft tissue Soft tissue abnormalities are the predominant

cause of posterior instability Posterior capsular shift

Anterior/posterior approach Posterior capsule thin 1.5mm Staples fallen out of favour Recent report 13/14 patients were satisfied at 44/12

follow-up Recurrence rate 30% some studies 50% high level athletes return to sports

OPEN TECHNIQUES - 2 Bone

Glenoplasty Glenoid retroversion/hypoplasia Opening wedge osteotomy Cadaveric studies confirm effective change in Glenoid

shape and increased stability Recent study 17 patients atraumatic posterior

instability at 5 year follow-up 81% rated good to excellent 12.5% had a recurrence Post-op degenerative changes were seen in 25% Recommended glenoplasty if glenoid retroversion 7-10°

radiographically Humeral Osteotomy

External rotation osteotomy Indicated if symptoms worsened on internal rotation Few reports in literature

POSTERIOR STABILISATION - 1

Lateral decubitus position +/- arthroscopic evaluation – rule

out anterior labral injury A 10cm saber cut incision from

posterior aspect AC joint to posterior axillary fold

POSTERIOR STABILISATION - 2

Deltoid split in line with its fibres from scapular spine 5cm distally

+/- detachment deltoid

POSTERIOR STABILISATION - 3

Fascial layer covering teres minor and infraspinatus divided

Two choices Develop interval between infraspinatus and

teres minor Develop interval between two heads

infraspinatus identified by fat stripe

POSTERIOR STABILISATION - 4

Divided from tendon insertion to just medial to glenoid beware branches suprascapular nerve

1.5cm from glenoid Infraspinatus dissected free from

capsule

POSTERIOR STABILISATION - 5

Capsule divided lateral to medial in mid-portion +/- labral repair

T-capsular incision based medially along edge of labrum

Superior and inferior flaps tagged

POSTERIOR STABILISATION - 6

Inferior capsular flap advanced superiorly and medially and sutured to labrum

POSTERIOR STABILISATION - 7

Superior flap brought over inferior flap inferior and medially

Sutures tied in neutral rotation

POSTERIOR STABILISATION - 8

Split in capsule repaired Wound closed

POST-OPERATIVE MANAGEMENT

Abduction pillow for 3/52 in neutral rotation

At 3/52- Standard sling- ROM exercises- No forward flexion

At 6/52- Full ROM

At 12/52- Return to sport

COMPLICATIONS

Loss internal rotation secondary to over-tight posterior capsular repair

Suprascapular/axillary nerve injury Hardware problems Recurrence - 30%