Experience with steroid-induced avascular necrosis of the shoulder and etiologic considerations regarding osteonecrosis of the hip.

Nineteen of 97 patients with steroid-induced osteonecrosis had a lesion involving the head of the humerus, on one or both sides. The lesion usually began as a subchondral osteolytic area which often progresses to collapse. Articular cartilage separated from subchondral bone, either becoming detached as a free cap or at a later stage reattaching. Present evidence suggests that osteonecrosis of the femoral or humeral head should properly be classified as either traumatic (macrovascular injury) or embolic (microvascular injury) in nature. In 14 patients conservative treatment resulted in satisfactory function with only intermittent symptoms, and including pendulum exercises and avoidance of abduction, particularly against resistance. Five patients required replacement of 6 humeral head replacement arthroplasties with Neer's prosthesis.