This retrospective review of 50 osteonecrotic femoral heads in 36 young patients demonstrates the general futility of conservative treatment in slowing progression to total hip arthroplasty (THA). Etiologic factors, i.e., alcoholism, steroids, and idiopathic, did not appear to modify the rate or pattern of clinical deterioration. Pathogenetic stages, i.e., Ficat II to IV, seemed unrelated to the degree of disability. Despite modified weight-bearing, analgesics, and antiinflammatory agents, only three of 50 hips (6%) remained clinically stable and none improved. Thirty-four of the 50 osteonecrotic hips (68%) had been treated by THA after a mean interval of 16 months. In an additional four hips (8%) THA had been recommended, but not carried out. Progressive femoral head collapse was documented in 67% of the hips, the remainder, having reached an end stage (Ficat IV). This study confirms previous reports of the inability of bed rest, crutches, or other ambulatory aids to arrest the progression of femoral head collapse and increasing disability in young individuals with osteonecrosis of the hip.