Bristow-Latarjet Procedure

Coracoid transfer is the answer to a specific question, and the question is asked elsewhere. The condition is anterior shoulder instability; the lesion this operation does NOT address on its own is the Bankart, which is why a soft-tissue repair is the alternative when bone stock is adequate; and the measurement that decides between them is on glenoid bone loss in instability, read together with the humeral side - the Hill-Sachs lesion and its own operation, remplissage, since bipolar bone loss is assessed on the glenoid track rather than either defect alone. The nerve that makes the coracoid osteotomy consequential is the musculocutaneous, which enters coracobrachialis a few centimetres distal to the tip.

The burden. Anterior shoulder dislocation is the most common large joint dislocation, and recurrent instability develops in 50-90% of young athletes after a first dislocation. Glenoid bone loss is present in up to 70% of recurrent dislocators, and in approximately 20% of them the loss exceeds a quarter of the glenoid - the inverted pear glenoid, which is the group this operation is for.

What is asked. Examiners want the difference between the Bristow and the Latarjet, the indication for coracoid transfer rather than arthroscopic soft-tissue repair, and the procedure's specific complications.

Why a soft-tissue repair fails once the rim has gone. Anterior glenoid bone loss is a bony deficiency and cannot be overcome by soft-tissue repair alone. A deficient anteroinferior rim leaves the labrum and capsule with no stable anchor point, and the humeral head translates over the deficient rim even after a Bankart repair.

The inverted pear. A normal glenoid is wider inferiorly than superiorly, the shape of a pear. Once enough anteroinferior bone has gone the superior width equals or exceeds the inferior width and the pear inverts. The sign is a reliable indicator on imaging that arthroscopic Bankart repair alone will have unacceptably high failure rates.

The glenoid track. The track is the contact area of the humeral head on the glenoid through the arc of motion, and its width is approximately 84% of the glenoid width. A Hill-Sachs lesion that stays inside the track is on-track and does not engage; one whose width plus the bone defect exceeds the track is off-track, engages and dislocates.

The triple blocking effect. Patte's rationale for the operation, and the three mechanisms that explain why a coracoid transfer succeeds where a Bankart repair fails in bone loss:

• Bone block - the coracoid graft replaces the missing anterior-inferior glenoid bone
• Sling effect - the conjoint tendon crosses the anteroinferior glenoid as a dynamic sling when the arm is abducted and externally rotated
• Soft tissue repair - capsulolabral reattachment to the CA ligament remnant restores the labral bumper

Three things get classified here: how much glenoid bone has gone, whether the Hill-Sachs lesion engages, and which version of the coracoid transfer is being described.

History. Establish the pattern of instability, what has already been done to the shoulder, and what the patient needs the arm to do. The answers that change management:

• Number of instability episodes, the mechanism, and whether this is a first dislocation or a recurrence
• Any previous Bankart repair or stabilisation, and what was done
• Functional demands: contact sport, overhead athlete, manual labourer
• Numbness or weakness after dislocation episodes

Examination. Confirm that the instability is anterior, then look for the findings that change the plan rather than confirm the diagnosis.

• Apprehension test - positive in anterior instability in abduction-external rotation
• Relocation test - apprehension relieved by a posteriorly directed force
• Load and shift - anterior and posterior translation, graded 0-3
• Beighton score - generalised ligamentous laxity; the hypermobile patient needs a different approach
• Rotator cuff assessment, to exclude concomitant cuff pathology

Choosing between a Bankart repair and a coracoid transfer. Recurrence is the arithmetic behind the threshold: arthroscopic Bankart repair is quoted at 5-15% in the shoulders selected for it, but once bone loss passes a quarter of the glenoid its failure rate exceeds 30%, against 1-5% after Latarjet. The lower edge of the borderline band is quoted variously as 13% and as 15%, and inside that band the decision turns on the patient rather than the percentage: contact or collision sport, an engaging Hill-Sachs lesion, and whether a soft-tissue repair has already failed.

Radiographs first, and expect them to understate the problem. A true AP, an axillary, a Stryker notch and, where available, a Bernageau view. The Stryker notch shows the Hill-Sachs lesion, the axillary shows glenoid rim fracture or erosion, and hardware from prior surgery is looked for. Plain films underestimate glenoid bone loss compared with CT.

CT is mandatory for any patient being considered for a Latarjet. Thin-slice acquisition with three-dimensional reconstruction and an en-face (sagittal oblique) glenoid view. Measurement is by the best-fit circle method: a circle is fitted to the inferior glenoid rim, which is typically intact in anterior bone loss, and the missing anterior bone is expressed as a percentage of the circle diameter. An inverted pear, superior width greater than or equal to inferior width, confirms loss of greater than 25 percent.

Where the inverted pear can be looked for. Three-dimensional CT with a Bernageau view, the best-circle fit method on an AP or axillary radiograph, or MRI with sagittal oblique reconstructions.

MRI for what the CT does not show. Labrum, capsule, rotator cuff and articular cartilage: the Bankart lesion, labral tears, a HAGL, capsular volume and the dimensions of the Hill-Sachs. It is the study that finds the concomitant pathology to be planned for, and it is read alongside the CT rather than instead of it.

What is being moved. The coracoid process gives attachment to the conjoint tendon (short head of biceps and coracobrachialis), to pectoralis minor and to the coracoacromial ligament. The transfer keeps the conjoint tendon attached to the graft, which is what makes the dynamic sling across the anteroinferior glenoid possible, and releases the other two.

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The price of the operation. The overall complication rate is approximately 15-30%, and most of what goes wrong involves the graft or the metal holding it.

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Reading the figures. The 1-5% recurrence usually quoted for the Latarjet is a short- to mid-term number; beyond ten years it is 5-8%, and return to sport and patient-reported scores drift down over the same period as radiographic arthritis appears.

Who does well. A young patient having a primary bony procedure rather than a revision, with good bone quality and a graft positioned flush with the rim, and a contact athlete motivated for rehabilitation.

Who does badly. Revision surgery after several previous procedures, poor bone quality in an osteopenic coracoid, a medially malpositioned graft, post-operative stiffness, and the voluntary dislocator.

The trade-off. The Latarjet achieves the lowest recurrence rate of any instability procedure in the setting of bone loss, and pays for it with a higher complication rate than arthroscopic soft-tissue repair.