Latarjet / Coracoid Transfer for Anterior Shoulder Instability

Indications for Latarjet — When to Abandon Arthroscopic Bankart

Absolute Indications (strong evidence):

• Glenoid bone loss greater than 20–25% on 3D CT (best-fit circle method) — inverted pear morphology on plain radiograph is a clinical proxy
• Off-track Hill-Sachs lesion: Hill-Sachs interval wider than glenoid track (Di Giacomo glenoid track concept) even with bone loss less than 20%
• Failed arthroscopic Bankart with recurrent instability — especially with progressive bone loss
• ISIS score 6 or greater in a contact athlete — 70% predicted failure rate from arthroscopic Bankart justifies primary Latarjet

Strong Relative Indications:

• Bone loss 13.5–20% with high-demand contact athlete (rugby, football) or ISIS score 4–5
• Epilepsy with recurrent seizure-related dislocations — repeated re-dislocation risk mandates durable bone reconstruction
• Poor labral tissue quality (attenuation, absence, prior failed repair) — no tissue to repair arthroscopically
• Significant Hill-Sachs lesion (greater than 25% humeral head width) where remplissage would excessively limit external rotation

Instability Severity Index Score (ISIS) — Balg & Boileau: A 10-point pre-operative score (range 0–10). A score greater than 6 points predicts a 70% recurrence risk after arthroscopic Bankart repair, supporting primary Latarjet in these patients. Note the score caps at 10, not 11.

Latarjet vs Bankart vs Remplissage — Decision Algorithm

Evidence Base

Burkhart and De Beer (2000, PMID 11027751) — landmark case series of 194 arthroscopic Bankart repairs establishing bone loss as the primary determinant of failure. Patients with significant bone defects (inverted-pear glenoid or engaging Hill-Sachs) had a 67% recurrence rate vs 4% without; contact athletes with bone deficits had 89% recurrence. Introduced the "inverted pear" and "engaging Hill-Sachs" concepts and recommended Latarjet for significant glenoid loss.

Balg and Boileau (2007, PMID 17998184) — derived and validated the Instability Severity Index Score (ISIS) in 131 patients. A pre-operative score greater than 6 points carried a 70% recurrence risk after arthroscopic Bankart, on which basis the authors recommended a Latarjet (Bristow-Latarjet) procedure instead. Changed worldwide practice toward primary bony stabilisation in high-risk patients. (Often cited as "Boileau 2005"; the validated 10-point score was published by Balg and Boileau in 2007.)

Yamamoto and Itoi (2007, PMID 17644006) — cadaveric study defining the glenoid track: the medial margin of the contact zone lies a mean 84% of the glenoid width medial to the rotator-cuff footprint. A Hill-Sachs lesion that extends medial to the track ("off-track") is at risk of engagement, providing the biomechanical basis for selecting bony augmentation in bipolar bone loss even with sub-critical glenoid defects.

Shah et al. (2012, PMID 22318222) — single-centre series of 48 Latarjet shoulders reporting early complications. Overall complication rate 25%: recurrent instability 8%, neurologic injury 10% (musculocutaneous, axillary and radial; most transient sensory neurapraxia resolving within 2 months), and superficial infection 6%. Highlights that the true early complication burden is higher than often quoted and must be included in consent.

Key Evidence — Verified

Subscapularis — The Critical Splitting Plane

Anatomy of split:

• Subscapularis origin: costal surface of scapula (subscapular fossa), inserting onto lesser tuberosity via broad tendinous insertion and capsular contributions
• The muscle has distinct upper and lower neurovascular territories (upper subscapular nerve L=C5 supplies upper portion; lower subscapular nerve C5–C6 supplies lower)
• Split location: junction of LOWER two-thirds and UPPER one-third — this level is critical
• Splitting here preserves the lower two-thirds as an intact musculo-tendinous unit that becomes the sling
• Horizontal, blunt split 2–3 cm in length, developed with index fingers; stay medial to bicipital groove

Why the split level matters (key exam concept): The lower two-thirds of subscapularis, when intact, creates the sling mechanism. In abduction-external rotation (the position of instability), the inferior subscapularis fibres tense across the anterior glenoid — this is the primary stabiliser after Latarjet, persisting even when the bone graft lyses.

Coracoid Process and Conjoint Tendon

Coracoid anatomy:

• Projects anterolaterally from supraglenoid scapular base
• Tip lies 1–2 cm medial and 1–2 cm inferior to the acromioclavicular joint
• Pectoralis minor inserts on medial coracoid (released during harvest)
• Coracobrachialis and short head biceps originate at the tip (preserved as conjoint tendon)
• Coracoacromial ligament: lateral coracoid to acromion — lateral 1 cm preserved with graft (capsular repair later)

Coracoid harvest dimensions:

• Harvest 2.0–2.5 cm of coracoid (measured from tip)
• Osteotomy at coracoid base (just medial to coracoclavicular ligament attachment)
• Graft provides articular cartilage-equivalent surface (deep coracoid surface is hyaline-like fibrocartilage)
• Flat inferomedial surface of coracoid = graft contact face with glenoid

Musculocutaneous Nerve — Most Important Nerve at Risk

Course and vulnerability:

• Arises from lateral cord (C5–C7)
• Exits lateral to pectoralis minor, passes laterally to pierce coracobrachialis
• Enters coracobrachialis 3–8 cm from coracoid tip (mean 5.4 cm, range 3–10 cm depending on patient height)
• Travels between biceps and brachialis to become the lateral antebrachial cutaneous nerve
• Risk: distal retraction of conjoint tendon greater than 2–3 cm stretches nerve; aggressive retraction hooks cause neuropraxia or axonotmesis

Clinical consequence of injury:

• Weak elbow flexion (biceps + brachialis), weak supination (biceps)
• Numbness lateral forearm (lateral antebrachial cutaneous nerve territory)
• Electromyography shows denervation in biceps and brachialis; lateral antebrachial cutaneous sensory nerve action potential absent

Axillary Nerve

• Exits quadrangular space with posterior circumflex humeral artery, courses anteroinferiorly along inferior subscapularis
• Lies approximately 12–15 mm inferior to glenoid rim at 6 o'clock position
• Risk during inferior dissection for glenoid exposure and in placing inferior screws
• Injury: deltoid paralysis, lateral shoulder numbness — rare in Latarjet (less than 0.5%) but catastrophic

Anterior Circumflex Humeral Vessels

• Arise from axillary artery third part, run along subscapularis lower border
• Contribute to humeral head blood supply (arcuate artery via anterolateral head)
• Risk during inferior capsulotomy — cauterise with bipolar before division

Positioning

• Beach chair position: 30–45 degrees head-up, head in neutral on padded horseshoe
• Arm free-draped over edge of table; arm holder optional but permits single-surgeon technique
• Ipsilateral arm in slight abduction and forward flexion for exposure
• Mark coracoid tip, anterior acromion edge, deltopectoral groove before prep

Step 1 — Skin Incision and Deltopectoral Approach

• Incision: 6–8 cm from 2 cm medial to coracoid tip, curving distally along deltopectoral groove toward insertion of deltoid
• Internervous plane: deltopectoral interval (deltoid innervated by axillary nerve; pectoralis major by medial and lateral pectoral nerves) — truly internervous
• Identify cephalic vein in groove; retract laterally with deltoid (preserves venous drainage, reduces haematoma risk)
• Develop interval sharply distally; identify coracoid tip under clavipectoral fascia
• Incise clavipectoral fascia lateral to conjoint tendon to expose subcoracoid space

Step 2 — Coracoid Harvest

• Release pectoralis minor from medial coracoid surface under direct vision
• Score coracoacromial ligament 1 cm from coracoid tip (lateral stump preserved for later capsular repair)
• Place curved Hohmann retractor under coracoid base; protect brachial plexus medially
• Osteotomy: oscillating saw or 15 mm osteotome at coracoid base, perpendicular to coracoid shaft
• Deliver coracoid graft; confirm 2.0–2.5 cm length
• Prepare flat surface: rongeur or high-speed burr to flatten inferomedial coracoid surface (this will contact glenoid neck)
• Drill two parallel holes through graft, 25–30 mm apart, for 3.5 mm cortical screws (countersink entry holes)

Step 3 — Subscapularis Split

• Identify subscapularis tendon; mark junction of lower two-thirds and upper one-third with electrocautery
• Horizontally split subscapularis with scissors and index finger, length 3–4 cm, from lateral tendon toward medial muscle
• Retract upper and lower halves with blunt self-retaining retractors
• Exposure of anterior shoulder capsule and glenoid neck

Step 4 — Anterior Capsulotomy and Glenoid Bed Preparation

• Incise anterior capsule horizontally in line with subscapularis split
• Elevate capsulolabral tissue from anterior glenoid neck subperiosteally (Cobb elevator)
• Decorticate anteroinferior glenoid neck with rongeur or burr to create bleeding cancellous recipient bed
• Recipient bed dimensions: approximately 20 mm wide by 25 mm tall (matches coracoid graft footprint)
• Confirm glenoid articular margin with probe — graft surface must end flush with this margin

Step 5 — Graft Positioning and Fixation

• Pass coracoid graft through subscapularis split with flat surface facing glenoid neck
• Conjoint tendon lies below the split (inferiorly) — this is the sling position
• Align graft so inferior edge is at 4–5 o'clock position on glenoid (covers the critical anteroinferior defect)
• Key checkpoint: graft articular surface must be flush (0–1 mm) with glenoid articular cartilage — NOT medial, NOT lateral
• Temporary K-wire through graft into glenoid to hold position
• Confirm position with intraoperative fluoroscopy (axillary view) before definitive fixation
• Insert proximal 3.5 mm cortical screw first, then distal screw; tighten sequentially
• Confirm both screws parallel, within graft, not penetrating posterior glenoid cortex

Step 6 — Capsular Reconstruction

• Suture the lateral stump of coracoacromial ligament (preserved during harvest) to the medial capsular tissue (residual anterior capsule and labrum)
• 2–3 interrupted absorbable sutures (#1 Vicryl or equivalent)
• This provides the third mechanism of stability — capsular reconstruction

Step 7 — Closure

• Confirm haemostasis, copious irrigation
• Subscapularis split does NOT require formal repair (closes spontaneously as arm adducts)
• Close deltopectoral fascia with absorbable sutures
• Subcutaneous and skin closure per surgeon preference
• Sling applied — arm in 15 degrees of forward flexion and neutral rotation

Sling Mechanism — The Key Biomechanical Concept

In abduction-external rotation (ABER), the conjoint tendon lying inferior to the subscapularis split tenses, transmitting compressive force to the anteroinferior glenoid. This is the dynamic anterior buttress effect, independent of graft osseous healing. Even if the graft lyses completely over years, the sling remains — provided the split is at the correct level and the tendon is not damaged.

Neurological Complications

Musculocutaneous nerve (most common — 0.8–8%):

• Transient neuropraxia from retraction far more common than axonotmesis
• Presents postoperatively as weak elbow flexion, lateral forearm numbness
• Most recover within 3–6 months with conservative management
• Prevention: limit conjoint tendon retraction to less than 2–3 cm distal to coracoid; identify nerve before distal release; gentle retraction with flat retractors rather than hooks

Axillary nerve (less than 0.5%):

• Risk during inferior capsulotomy and inferior screw placement
• Deltoid paralysis and lateral shoulder numbness
• Identify nerve on inferior subscapularis surface before inferior dissection

Hardware Complications

• Screw back-out (3–5%): more common with cancellous screws; use cortical screws
• Screw prominence (2–3%): proud screws abrade humeral head cartilage — early sign is mechanical grinding; requires early revision before articular damage
• Graft non-union (2–5%): asymptomatic non-union does not require revision; symptomatic non-union with instability may require revision fixation or bone grafting

Graft Lysis

• CT evidence of graft resorption in 15–30% at 5 years
• Does NOT equal failure — sling mechanism persists
• Revision surgery only if: (1) symptomatic recurrent instability AND (2) CT confirms sling mechanism compromised (graft medially displaced, conjoint tendon detached)
• Factors associated with lysis: screw divergence, thin graft, excessive bone bed preparation, infection

Subscapularis Dysfunction

• Split too superior (at or above midpoint) damages the upper half responsible for internal rotation strength
• Presents as weakness of internal rotation and positive lift-off or belly-press test
• Ultrasound or MRI confirms split level and integrity
• Most respond to physiotherapy; chronic dysfunction with functional impairment may require subscapularis repair

Glenohumeral Arthritis

• Arthritis progression is the most significant long-term concern
• 30% radiographic arthritis at 10 years (comparable to post-instability arthritis without surgery)
• Causes: over-lateral graft (proud screw heads), hardware impingement, loss of normal articular geometry
• When severe: reverse shoulder arthroplasty preferred over anatomic TSA (subscapularis unreliable after Latarjet)

Postoperative Protocol

Phase 1 — Protection (Weeks 0–4):

• Sling in 15 degrees forward flexion and neutral rotation
• Pendulum exercises from day 1 (gravity-assisted circumduction)
• Hand, wrist, elbow ROM exercises unrestricted
• No active shoulder motion against resistance
• Ice pack 20 minutes three times daily for first 2 weeks

Phase 2 — Early Motion (Weeks 4–8):

• Sling discontinued at 4 weeks
• Active-assisted ROM: elevation in scapular plane to 90 degrees, external rotation to neutral then 20 degrees
• Begin formal physiotherapy: scapular stabilisation, periscapular strengthening, postural correction
• No strengthening of subscapularis or internal rotators until week 6

Phase 3 — Strengthening (Weeks 8–16):

• Full active ROM exercises
• Progressive rotator cuff strengthening programme
• Closed-chain shoulder proprioception exercises
• Sport-specific drills commenced at 12 weeks (non-contact)
• CT scan at 12 weeks to confirm graft incorporation (optional, per surgeon preference)

Phase 4 — Return to Sport (Months 4–6):

• Contact training commenced at 4 months when full strength and ROM achieved
• Full contact sport return at 6 months minimum
• Criterion-based discharge: symmetrical strength testing (greater than 90% limb symmetry index), full pain-free ROM, sport-specific movement competency

Rehabilitation Milestones Comparison

Expected Outcomes at Follow-up

• Recurrence rate: 5–8% overall; 2–4% in appropriately selected patients at 10 years
• Return to sport: 74–97% across series; contact athletes 80–90%
• External rotation loss: mean 5–10 degrees — clinically acceptable in most patients
• Graft healing: CT confirmed union in 70–85% at 6 months
• Patient satisfaction: 85–95% satisfied or very satisfied at 5 years