Osteonecrosis of the hip: novel approaches to evaluation and treatment.

The treatment of osteonecrosis of the hip remains a dilemma. Contemporary basic science research focuses on establishing the molecular etiology of this disease with the hope of identifying targets for pharmacologic intervention. Researchers have identified specific genetic polymorphisms that may predispose its development and these may allow early diagnosis and treatment of at-risk patients. Refinements in magnetic resonance imaging aid in the staging of patients with osteonecrosis and findings appear to correlate with clinical outcome. Novel nonoperative and operative modalities for the treatment of osteonecrosis are also under investigation. The results of new pharmacologic and biophysical treatments appear beneficial in delaying, and possibly preventing, the progression of precollapse lesions. New bone grafting strategies may enhance the results of core decompression. Although the results of conventional total hip arthroplasty have improved, newer surface replacement systems provide satisfactory short-term outcomes and may preserve bone stock in younger patients. Further research is needed to clarify the roles of these emerging technologies in the treatment of osteonecrosis of the hip. Until there is convincing evidence of efficacy in randomized clinical trials, we recommend appropriate staging and core decompression with or without bone graft for precollapse lesions and total hip arthroplasty or surface replacement for advanced disease.