Core decompression in osteonecrosis of the femoral head: risk-factor-dependent outcome evaluation using survivorship analysis.

The results of core decompression of the femoral head in the treatment of osteonecrosis are analyzed. This study includes 94 hips in 74 patients with a follow-up time ranging between 18 months and 15 years (average 6 years). There had been no need for further surgery 2 years postoperatively in 85% of the hips with preoperative Steinberg stages 0, I and II when compared with 66% with preoperative stages III, IV and V. At 4 years postoperatively the corresponding figures are 73 compared to 55%; and 6 years postoperatively 69 compared to 49%. This difference was significant (P=0.0402). Further significant risk factors are corticosteroid administration, smoking and alcohol intake. The results of core decompression are good when the preoperative lesion is at Steinberg stage 0, I and II and the patient does not present with other risk factors. In cases with risk factors the outcome is significantly less good. The procedure is not indicated in the presence of advanced disease.