Shoulder Instability — Bankart/Latarjet

Shoulder instability encompasses a spectrum from subtle microinstability to frank recurrent dislocation. Anterior glenohumeral instability is by far the most common type, accounting for over 95% of cases. The condition disproportionately affects young active males and athletes, and carries a high recurrence risk when managed non-operatively in this demographic.

• Incidence of first-time anterior dislocation: approximately 17 per 100,000 population per year
• Recurrence risk after first dislocation: up to 90% in patients under 20 years; decreases with increasing age
• Recurrence rates in patients over 40 years: approximately 10–15%, but rotator cuff tears are more common in this group
• Contact sport athletes and overhead athletes have the highest recurrence risk
• Posterior instability accounts for approximately 2–5% of cases; multidirectional instability (MDI) is less common and often associated with generalised ligamentous laxity
• Risk of axillary nerve injury with primary dislocation: approximately 5–35% — most resolve spontaneously

A thorough understanding of the stabilising structures and their failure patterns is essential to selecting the correct surgical procedure.

• Static stabilisers: glenoid shape and version, labrum, glenohumeral ligaments (superior, middle, inferior — IGHL most important), negative intra-articular pressure, capsular volume
• Dynamic stabilisers: rotator cuff (concavity-compression mechanism), biceps long head, periscapular muscles
• Inferior glenohumeral ligament (IGHL) — anterior band is the primary restraint to anterior translation with the arm in abduction and external rotation (ABER position)
• Bankart lesion: avulsion of the anteroinferior labrum and IGHL complex from the glenoid — present in approximately 85–97% of traumatic anterior dislocations
• Bony Bankart: glenoid rim fracture with labral avulsion — present in up to 22% of first-time dislocations; increases with recurrence
• Hill-Sachs lesion: posterolateral humeral head compression fracture from impaction against anterior glenoid rim — present in up to 80% of anterior dislocations
• Engaging Hill-Sachs: lesion that engages the anterior glenoid rim during functional range of motion — critical concept determining need for humeral-sided or combined bony procedure
• ALPSA lesion (anterior labroligamentous periosteal sleeve avulsion): labrum stripped medially with intact periosteum — more common in recurrent instability; requires specific surgical recognition
• HAGL lesion (humeral avulsion of glenohumeral ligament): IGHL avulses from humeral attachment — present in approximately 7–9% of instability cases; often missed on MRI; causes failure of Bankart repair if unrecognised

Bone loss assessment is the single most important preoperative step in planning surgical treatment for recurrent anterior instability. Failure to account for significant bone loss is the most common cause of recurrent instability after Bankart repair.

• Glenoid bone loss: measured on 3D CT with humeral head subtracted — en face view of glenoid; compared to the best-fit circle of the inferior glenoid
• Glenoid bone loss >20–25% = critical threshold — Bankart repair alone associated with unacceptably high recurrence rates; bony procedure (Latarjet or bony augmentation) indicated
• Glenoid bone loss <13.5%: bare spot method or best-fit circle method — soft tissue Bankart repair generally adequate
• Glenoid bone loss 13.5–20%: borderline zone — consider Latarjet, especially in high-demand athletes or contact sport participants
• Hill-Sachs interval (HSI) / Glenoid Track concept (Yamamoto/Di Giacomo): determines whether Hill-Sachs lesion will engage with the glenoid during functional ROM
• Off-track Hill-Sachs lesion (HSI > glenoid track width) = engaging lesion requiring treatment — either remplissage or Latarjet (which simultaneously increases glenoid track)
• On-track Hill-Sachs = non-engaging — soft tissue Bankart repair sufficient if glenoid bone loss is acceptable
• Glenoid track width = 0.83 × glenoid width − glenoid bone loss

• History: number of dislocations, mechanism (traumatic vs atraumatic), position of arm at time of dislocation, degree of force required for reduction, sport and activity level, generalised hyperlaxity, prior surgery
• Beighton Score: assess for generalised ligamentous laxity — score ≥4/9 suggests hyperlaxity; relevant for MDI diagnosis and surgical planning
• Anterior apprehension test: arm in ABER position — apprehension (not just pain) is the positive finding; most specific test for anterior instability
• Relocation test (Jobe): posterior pressure on humeral head relieves apprehension — confirms anterior instability
• Load and shift test: quantifies anterior, posterior, and inferior laxity; graded 0–3
• Sulcus sign: inferior traction on dependent arm produces subacromial depression — positive in inferior laxity and MDI; sulcus sign persistent in neutral and external rotation = pathological inferior laxity
• Assess axillary nerve function (regimental badge area) in all acute dislocations
• Assess rotator cuff integrity — especially in patients over 40 years with acute dislocation

• Plain radiographs: AP, true AP (Grashey), axillary lateral, Stryker notch view (Hill-Sachs), West Point view (anterior glenoid rim)
• MRI arthrogram: gold standard for labral pathology — superior to standard MRI for Bankart, ALPSA, HAGL, and partial labral tears; assess capsular volume and IGHL
• 3D CT with humeral head subtraction — mandatory for quantifying glenoid bone loss and planning bony procedure
• CT arthrogram: useful when MRI contraindicated; less sensitive for soft tissue detail
• Ultrasound: limited role in instability workup — not reliable for labral assessment

Arthroscopic Bankart repair is the gold standard for first-time or recurrent anterior instability with minimal bone loss and an on-track Hill-Sachs lesion in appropriate patients.

• Technique: anteroinferior labrum and IGHL complex mobilised from glenoid neck, advanced superiorly, and secured with suture anchors — typically 3 anchors; some advocate 4–5 anchors for larger repairs
• Capsular shift should be incorporated — reduces capsular volume and corrects patulous capsule
• Interval closure (rotator interval): controversial — may reduce external rotation; reserved for confirmed inferior laxity component
• Recurrence after arthroscopic Bankart: approximately 10–15% overall; up to 25–40% in contact athletes and those with unrecognised bone loss
• Predictors of failure: contact sport, age <20, >2 prior dislocations, bone loss, hyperlaxity, off-track Hill-Sachs, ALPSA lesion
• INSTABILITY SEVERITY INDEX SCORE (ISIS): preoperative scoring system — score >6 predicts high recurrence after Bankart; Latarjet recommended
• Remplissage (arthroscopic posterior capsulodesis + infraspinatus tenodesis into Hill-Sachs defect): converts off-track lesion to extra-articular; reduces engagement — loss of approximately 8–10° external rotation; good results in selected patients

The Latarjet procedure transfers the coracoid process with its attached conjoint tendon to the anterior glenoid, addressing bone loss and providing a triple blocking effect. It is increasingly used as a primary procedure in high-risk patients regardless of glenoid bone loss.

Triple Blocking Effect of Latarjet:

• 1. Bony block: coracoid graft extends the glenoid arc, increasing articular surface and reducing bone loss deficit
• 2. Sling effect: conjoint tendon acts as a dynamic sling under the subscapularis — tightens with arm in ABER position (the position of instability), preventing anterior humeral head translation
• 3. Capsulorrhaphy: remnant coracoacromial ligament sutured to anterior capsule and glenoid — reinforces the anterior soft tissue restraint

Surgical Technique:

• Deltopectoral approach; subscapularis split (horizontal split at junction of upper 2/3 and lower 1/3) — preserves subscapularis innervation and function
• Coracoid osteotomy 15–20 mm from tip — preserves pectoralis minor attachment; harvests adequate bone
• Graft positioned flush or slightly medial to glenoid articular surface — proud graft accelerates glenohumeral OA (Saragaglia sign)
• Fixed with two partially threaded cancellous screws — parallel screws perpendicular to glenoid face; divergent screw placement risks graft fracture
• Arthroscopic Latarjet: technically demanding but gaining popularity — similar recurrence rates, less soft tissue morbidity; steep learning curve

Outcomes:

• Recurrence rate: approximately 1–4% — superior to Bankart repair in high-risk patients and those with bone loss
• Return to sport at same level: approximately 75–80% in contact athletes
• Long-term OA risk: progressive glenohumeral OA reported in 10–20% at 10–25 years — related to graft position, screw prominence, and loss of external rotation

Complications specific to Latarjet:

• Musculocutaneous nerve injury (passes through conjoint tendon) — most common neurological complication
• Graft resorption, nonunion, fracture — rare but recognised
• Screw loosening or breakage
• Proud graft — accelerates OA; requires graft flush positioning
• Subscapularis dysfunction if split not repaired adequately

• Iliac crest bone graft (ICBG) / Eden-Hybinette: used for massive glenoid defects (>30–40%) or failed Latarjet; autograft iliac crest fashioned to reconstruct glenoid arc; more technically demanding
• Distal tibia allograft: closely matches glenoid concavity due to similar radius of curvature — good results reported; avoids donor site morbidity; gaining popularity as alternative to Latarjet in revision settings
• Humeral-sided procedures: Connolly / Weber rotational osteotomy — rarely used; for engaging Hill-Sachs without glenoid bone loss; technically demanding
• Failed Latarjet with significant residual bone loss — consider distal tibia allograft or iliac crest graft reconstruction

• MDI hallmark: sulcus sign present bilaterally, Beighton score elevated, no discrete labral pathology on MRI arthrogram
• Open inferior capsular shift (Neer-Foster): gold standard for MDI failing conservative treatment — tightens inferior pouch; recurrence rate approximately 5%
• Posterior bone block: indicated for posterior glenoid bone loss >15% or failed soft tissue posterior repair; reverse Latarjet increasingly described

• HAGL lesion: must be actively excluded on MRI arthrogram — look for J-sign (discontinuity of inferior axillary pouch contour); if present, requires open or arthroscopic repair at humeral attachment; unrecognised HAGL is a common cause of failed Bankart repair
• ALPSA vs Bankart: ALPSA has labrum displaced medially and inferiorly with intact periosteum — must be mobilised and advanced back to glenoid rim, not simply reattached in situ; failure to recognise leads to poor repair tension
• Glenoid track concept has largely replaced simple bone loss thresholds — a small Hill-Sachs with large bone loss can be off-track; a large Hill-Sachs with no bone loss can be on-track; always calculate both
• Proud Latarjet graft is the primary modifiable cause of long-term OA after the procedure — intraoperative fluoroscopy or arthroscopic confirmation of flush positioning is mandatory
• Subscapularis split vs tenotomy: horizontal split preserves the upper subscapularis and its blood supply — superior to tenotomy for functional outcome; repair meticulously at closure
• Arthroscopic vs open Latarjet: no significant difference in recurrence in experienced hands — arthroscopic approach reduces deltopectoral dissection but requires significant technical expertise; open remains gold standard for training and complex cases
• First-time dislocators in contact athletes under 25 years: emerging evidence (Kirkley, Bottoni, Handoll) supports primary surgical stabilisation in this demographic — significantly reduces recurrence and time to return to sport compared to non-operative treatment
• Patients over 40 years with acute first dislocation: always assess rotator cuff — concurrent cuff tear rate increases dramatically with age; missed cuff tear leads to persistent weakness and poor outcome

• Bankart lesion present in 85–97% of traumatic anterior dislocations — anteroinferior labrum avulsion with IGHL
• HAGL lesion — humeral-sided IGHL avulsion; causes failed Bankart if missed; look for J-sign on MRI arthrogram
• Glenoid bone loss >20–25% = Latarjet / bony procedure; Bankart alone will fail
• Off-track Hill-Sachs = engaging lesion = add remplissage or perform Latarjet (which increases glenoid track)
• Latarjet triple block: bony graft + sling effect of conjoint tendon + capsulorrhaphy
• Musculocutaneous nerve most at risk in Latarjet — passes through conjoint tendon
• Proud graft after Latarjet = accelerated glenohumeral OA — position flush with articular surface
• ISIS score >6 = high recurrence after Bankart — consider Latarjet primarily
• MDI: sulcus sign bilateral, no discrete labral tear, treat non-operatively first; open inferior capsular shift if fails
• ALPSA — medially displaced labrum with intact periosteum; must mobilise and re-advance; not same as standard Bankart repair
• Recurrence after Bankart in contact sport under 20 years = up to 90% — consider primary stabilisation