Management of Posterior Glenohumeral Instability With Large Humeral Head Defects

Traumatic posterior instability may occasionally cause a large osteochondral lesion when the anterior humeral head is compressed against the posterior glenoid rim. This is termed a reverse Hill–Sachs lesion. Such osteochondral defects may be very large in the case of chronic locked dislocations. Even in acute posterior disclocations, closed reduction may be difficult when the humeral head is locked posteriorly over the glenoid. In such cases closed or open reduction under general anesthesia with muscle relaxation may be necessary. In cases where the anterior humeral head defect is large, reconstruction may be necessary to maintain stability. Management must be tailored to the individual patient and depends on several factors, which include the size of the defect, the duration of the dislocation, the quality of the bone, the status of the articular cartilage, and the patient’s overall health. Treatment options include skillful neglect, subscapularis-lesser tuberosity transfer into the humeral head defect, disimpaction and bone grafting, allograft reconstruction of the humeral articular surface, and arthroplasty.