Biomechanics and management of HAGL lesions in Anterior Instability

Humeral avulsion of the glenohumeral ligament is an uncommon but important cause for recurrent anterior instability of the shoulder. It is usually associated with high energy trauma in a slightly older male population with a hyperabduction/axial load mechanism. Associated damage can include avulsion of the glenoid labrum, rotator cuff tears, and bony damage. Diagnosis requires a high index of clinical suspicion, and MR arthrography performed 4-6 weeks post injury is the most reliable investigation. Care should be taken with MRI performed in the first week, as many of the lesions seen at this time will heal. Surgical repair is recommended for recurrent instability or if the patient requirements require them to have a stable shoulder. Repair can be performed using arthroscopic, mini-open or full open techniques. Care should be taken when placing sutures through the capsule because of the proximity of the axillary nerve to the inferior capsular edge. Biomechanically, the capsule should be repaired to the medial humeral neck just below the chondral margin. Surgical outcomes are satisfactory in most series reported.