Cortisone-induced avascular necrosis of the femoral head.

Of ninety-five patients with corticosteroid-induced avascular necrosis of bone, ninety-one had involvement of the femoral head. The risk of developing this lesion appeared to be correlated with the total steroid dose. Forty-nine patients demonstrated a subchondral osteolytic defect which healed without proceeding to collapse. Four femoral heads in four patients developed sequestration, resembling osteochondritis dissecans, of a small area of the femoral head. Thirty-eight showed the classical lesion of subchondral osteolysis followed by collapse of the underlying bone. Operation was not necessary in the absence of subchondral collapse. All four patients with the lesion resembling osteochondritis dissecans required surgical replacement of their femoral heads because of disabling symptoms. Twenty of the thirty-eight patients with femoral head collapse required no operation because they either died from their systemic illness or were able to tolerate the level of disability. Eighteen patients required a total of twenty-five operations for disease involving the hips. Varus derotation osteotomy was of benefit in two patients with minimal lesions. When the acetabulum was normal femoral head replacement offered good relief. Total hip replacement has given satisfactory results when the acetabulum showed degenerative changes.