Long-term follow-up of total hip replacement in patients with avascular necrosis.

Long-term studies show that patients with osteonecrosis who undergo total hip replacement experience an overall failure rate four times greater than those with osteoarthritis. Different etiologic factors associated with osteonecrosis appear to carry different prognoses for the durability of total hip replacements. Important factors, in addition to discouraging total hip replacement in patients under 30 to 40 years of age and making all possible efforts to decrease the patient's weight and activity level, include improvements in bone quality, surgical and cementing techniques, prosthetic design, and materials that will prolong the durability of total hip replacements. Despite the inferior long-term results of total hip replacement performed for advanced osteonecrosis, we feel the procedure should not be abandoned for patients in their fifth decade of life or older because it provides a painless, functional hip more consistently than does any other form of arthroplasty. These patients should be informed about the importance of protecting the hip replacement by avoiding strenuous activities, impact, and obesity, and about the possibilities of future mechanical failure that may require revision surgery. Although significant improvements have been made in regard to the technology of total hip replacement, future research in the bone biology of osteonecrosis is necessary.