Role of impairment of blood supply of the femoral head in the pathogenesis ³

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of idiopathic osteonecrosis. Atsumi T. Kuroki Y. Clinical Orthopaedics & Related Research. (277):22-30, 1992 Apr. Conservative treatment versus core decompression for cases of osteonecrosis (ON) of the femoral head was prospectively reviewed in 36 patients. A preoperative evaluation of the patients' history, physical examination, Harris Hip Score, roentgenograms, computed tomography, bone Á scan, magnetic resonance imaging, and measurement of the intraosseous  pressure was used to grade the level of ON according to a rating system developed by Ficat. Hips were randomized to core decompression or conservative treatment groups. Fifty-five hips in 36 patients were randomized (29 surgical and 26 conservative). When success was gauged by Harris Hip Scores for Stage I hips, treatment was successful for seven of ten (70%) operatively treated hips and one of five (20%) non-operatively treated hips. Among Stage II hips, treatment was successful for five of seven (71%) decompressed hips and none of seven conservatively treated hips. Successful treatment was accomplished in eight of 11 hips (73%) and one of ten hips (10%) in decompression and conservative groups, respectively, for Stage III hips. Stages 0 and IV had groups too small for comparison. Less successful results were seen if roentgenographic criteria * of success were used. Survival analysis showed more favorable results with surgical treatment. Core decompression produced better results than Á conservative treatment in the early stages of ON. *