Shoulder Dislocations

The shoulder is the most common major joint dislocation, and management has evolved with evidence supporting early surgical stabilisation in young athletes. Recurrence risk, the associated lesions and the surgical indications are what the examination tests.

Who. The distribution is bimodal: young males injured in sport and elderly patients who fall. Men outnumber women 2.5:1, incidence peaks at 20-30 years, and contact sports such as AFL and rugby carry the highest risk.

What it costs. Time off work or sport during recovery, a high recurrence rate in young patients and the risk of progressive bone loss. For an athlete it can be career-ending.

Mobility bought with stability. The glenohumeral joint sacrifices stability for mobility. The glenoid covers only 25-30% of the humeral head, so the joint relies on the labrum, capsule and rotator cuff to stay located. The labrum increases socket depth by 50% and contact area by 75%.

History. The answers that change management:

• Mechanism - ABER for anterior, seizure for posterior
• First or recurrent episode - recurrence is the key question
• How it was reduced - by the patient or in the emergency department
• Sport and occupation - contact sport, overhead work
• Hand dominance, which affects the surgical decision
• Previous treatment - physiotherapy, surgery, bracing

Examination. The two directions look different, and the posterior one is the one that gets missed.

The axillary nerve. It is injured in up to 30% of anterior dislocations, and it runs just below the inferior capsule. Test deltoid power in abduction and sensation over the regimental badge area of the lateral deltoid, before and after any reduction. Document both: it is a medicolegal requirement.

The instability examination. Once the shoulder is reduced the apprehension test is positive. For anterior instability the sequence is apprehension, then relocation, then surprise:

• Apprehension test - the arm abducted to 90 degrees and progressively externally rotated (ABER). A positive test is the fear that it will dislocate, not pain, reproducing the unstable position
• Relocation (Jobe) test - from the apprehensive position, a posteriorly directed force on the proximal humerus relieves the apprehension, confirming anterior instability
• Surprise (release) test - suddenly releasing that force brings the apprehension back; the most specific sign of anterior instability

Laxity, its direction and degree.

• Load-and-shift - load the head axially into the glenoid, then translate it anteriorly and posteriorly and grade the translation
• Sulcus sign - downward traction with the arm at the side produces a dimple below the acromion, showing inferior laxity. If it persists in external rotation it suggests a rotator-interval lesion; it is a hallmark of multidirectional instability and generalised laxity
• Gagey hyperabduction test - passive glenohumeral abduction beyond about 105 degrees, compared with the other side, indicates inferior glenohumeral ligament laxity

Posterior instability. In the jerk and Kim tests an axial load on the flexed, adducted, internally rotated arm, moved into abduction for the jerk test, produces a clunk with a posterior labral lesion. Screen too for generalised ligamentous laxity with the Beighton score, which points toward atraumatic or multidirectional instability.

Radiographs. A trauma series, before and after reduction. Never rely on the AP alone: the axillary or Y view is what excludes a posterior dislocation.

• True AP in the scapular plane
• Axillary lateral - shows the head's position relative to the glenoid, and is essential when posterior dislocation is suspected. If the patient cannot abduct, the Velpeau view is the alternative: arm across the chest, leaning back
• Scapular Y - in a posterior dislocation the head sits behind the glenoid

After reduction, repeat the trauma series to confirm it, and document any fracture now visible.

Posterior dislocation on the AP. The AP may look normal, so look for:

• Lightbulb sign - the internally rotated head looks round like a lightbulb, its normal contour lost
• Rim sign - the distance between the medial head and the anterior glenoid rim is over 6mm, widening the joint space
• Trough sign - a vertical sclerotic line on the medial head, the reverse Hill-Sachs impaction seen en face
• Lost half-moon - the normal overlap of the head on the glenoid rim disappears as the head displaces posteriorly

MRI or CT. MRI is best for the labrum (Bankart), capsule and rotator cuff. CT is best for quantifying bone loss, glenoid and humeral.

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Measuring glenoid bone loss. Use an en-face view of the glenoid on 3D CT. The normal inferior two-thirds of the glenoid is a circle, and bone loss is calculated as the percentage of that intact circle that is missing.

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Algorithm

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Acute ReductionFirst-Time DislocationRecurrent InstabilityPosterior Dislocation

Reduction Methods

PreferredStimson Technique

Patient prone, arm hanging off the table with a 2-5kg weight attached, and gentle internal and external rotation. It uses gravity and muscle fatigue, and the least force.

AlternativeExternal Rotation Method

Patient supine, elbow at 90°. Slow external rotation while adducting the arm. Gentle, low force, minimal sedation.

No TractionCunningham Technique

Patient seated and leaning forward while the biceps, deltoid and trapezius are massaged to relax them. No traction - muscle relaxation only.

HistoricalHippocratic/Kocher

Traction-countertraction methods, higher force and historical. Kocher has fracture risk - avoid.

After reduction. Repeat and document the neurovascular examination, confirm the reduction on X-ray, immobilise in a sling, give analgesia, and arrange follow-up and an MRI.

When it will not reduce. Tissue may be interposed (rotator cuff, biceps), a fracture may block it, or the anaesthesia may be inadequate. Open reduction may be needed.

Age sets the risk. The recurrence figures below are the commonly quoted short-to-medium-term series figures:

Under 20 years

Recurrence Risk

90%

Management

Consider early arthroscopic Bankart repair

Evidence

RCTs show reduced recurrence

20-30 years, athlete

Recurrence Risk

60-70%

Management

Consider early stabilisation in contact sport

Evidence

Shared decision-making

30-40 years

Recurrence Risk

40-50%

Management

Conservative, physio, reassess if recurs

Evidence

Recurrence lower, surgery if fails

Over 40 years

Recurrence Risk

Under 25%

Management

Conservative, check rotator cuff on MRI

Evidence

High cuff tear rate - address if present

Age Group	Recurrence Risk	Management	Evidence
Under 20 years	90%	Consider early arthroscopic Bankart repair	RCTs show reduced recurrence
20-30 years, athlete	60-70%	Consider early stabilisation in contact sport	Shared decision-making
30-40 years	40-50%	Conservative, physio, reassess if recurs	Recurrence lower, surgery if fails
Over 40 years	Under 25%	Conservative, check rotator cuff on MRI	High cuff tear rate - address if present

Adults and the elderly. Between 30 and 50, treat conservatively: a sling for 2-4 weeks, activity modification and physiotherapy. Over 60, conservative care with early motion, and check the rotator cuff because the tear rate is high.

The controversy. In first-time dislocators under 25 in contact sports, early stabilisation clearly reduces recurrence, but quote the trials individually rather than as one range. The conservative arms recurred in 47% (Kirkley, n=40), 56% (Jakobsen, n=76) and 75% (Bottoni, n=21 analysed, military athletes); the operative arms in 16%, 3% and 11% respectively. The often-quoted "90%" is not the figure from any of these trials.

The counterweight. Hovelius's 25-year prospective series found that roughly half of 12-25 year olds either never recurred or stabilised over time. By 25 years 38% of that age group had been stabilised surgically, and 27% of all the shoulders in the series had been operated on. That is why conservative treatment with informed patient choice remains defensible even in this age group.

Algorithm

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Algorithm

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Arthroscopic Bankart repair

Indication

Glenoid bone loss under 25%, no engaging Hill-Sachs

Key Points

Gold standard soft tissue repair, 10-15% recurrence

Latarjet procedure

Indication

Glenoid bone loss over 25%, revision Bankart failure

Key Points

Coracoid transfer, 5% recurrence

Remplissage

Indication

Large Hill-Sachs, off-track lesion

Key Points

Infraspinatus tenodesis into Hill-Sachs defect

Open Bankart repair

Indication

HAGL lesion, capsular shift needed

Key Points

Lower recurrence in some studies, bigger incision

Procedure	Indication	Key Points
Arthroscopic Bankart repair	Glenoid bone loss under 25%, no engaging Hill-Sachs	Gold standard soft tissue repair, 10-15% recurrence
Latarjet procedure	Glenoid bone loss over 25%, revision Bankart failure	Coracoid transfer, 5% recurrence
Remplissage	Large Hill-Sachs, off-track lesion	Infraspinatus tenodesis into Hill-Sachs defect
Open Bankart repair	HAGL lesion, capsular shift needed	Lower recurrence in some studies, bigger incision

Latarjet Complications

The Latarjet has a higher complication rate than a Bankart repair: nerve injury (musculocutaneous, axillary), nonunion, hardware problems and OA. Reserve it for true bone loss over 25% or a failed Bankart. It is not a first-line procedure.

Management Steps

RecognitionStep 1

Recognise the diagnosis: a history of seizure, the arm fixed in IR, unable to ER. Get an axillary view.

CT ScanStep 2

CT, before or after reduction, to assess the size of the reverse Hill-Sachs and the chronicity. Defect size guides treatment.

ReductionStep 3

Traction, adduction, then gentle external rotation. May need GA, and is often more difficult than an anterior reduction.

Post-Reduction AssessmentStep 4

Assess stability in external rotation. If it is unstable, or the reverse Hill-Sachs is large, surgery is likely to be needed.

Under 20%

Management

Immobilise in external rotation, physiotherapy

20-40%

Management

Lesser tuberosity transfer (McLaughlin) or allograft

40-50%

Management

Consider hemiarthroplasty or reverse TSA

Over 50%

Management

Arthroplasty (reverse TSA in elderly)

Reverse Hill-Sachs Size	Management
Under 20%	Immobilise in external rotation, physiotherapy
20-40%	Lesser tuberosity transfer (McLaughlin) or allograft
40-50%	Consider hemiarthroplasty or reverse TSA
Over 50%	Arthroplasty (reverse TSA in elderly)

Multidirectional instability. MDI is a distinct entity, managed completely differently from the traumatic Bankart shoulder, and a favourite exam trap. It is symptomatic instability in two or more directions, usually inferior plus anterior or posterior, typically atraumatic or from repetitive microtrauma, in patients with generalised ligamentous laxity and a high Beighton score. Swimmers, throwers and gymnasts are the classic patients.

What to find. The hallmark is a positive sulcus sign, often bilateral, with no discrete Bankart or bony lesion. The problem is a redundant, capacious capsule.

Rehabilitation first. Prolonged, structured rehabilitation (the Rockwood-type programme) strengthens the rotator cuff and scapular stabilisers dynamically and trains proprioception, and the majority improve and avoid surgery. A muscle-patterning or voluntary component (Stanmore Pole III) is treated with biofeedback or psychology rather than an operation.

Surgery after a genuine failed trial of 6 months or more. An inferior capsular shift (Neer) or capsular plication, open or arthroscopic, reduces capsular volume in all directions, often with rotator-interval closure.

Axillary nerve recovery. 90% of axillary nerve injuries recover within 3-6 months. If there is no clinical recovery by 3 months, obtain EMG/NCS, and consider exploring the nerve if there is none by 6-9 months.

Surgery or not for the first dislocation. RCT evidence (Kirkley, Jakobsen) shows that early stabilisation cuts recurrence, and Hovelius shows that many young dislocators stabilise without surgery; the figures are under First-Time Dislocation above. The genuine debate is patient selection; whether surgery works is not in question.

The Bankart-Latarjet threshold. The classic 25% glenoid bone-loss cut-off is being challenged by data on subcritical bone loss (around 13.5-20%), suggesting that a Bankart alone may underperform earlier than thought, especially in contact athletes.

Remplissage or bony augmentation. For an off-track Hill-Sachs with subcritical glenoid loss, Bankart plus remplissage and Latarjet give comparable recurrence, with fewer complications reported for remplissage. The optimal choice remains unsettled.

Immobilisation position. Some studies (Itoi) suggested that immobilising in external rotation reduces recurrence by approximating the Bankart lesion to the glenoid. Meta-analyses show no significant difference, the pooled data (Paterson) only a non-significant trend, and most units default to a short period in a standard internal-rotation sling, which is easier.