Avascular femoral head necrosis in pediatric cancer patients.

Avascular femoral head necrosis was identified in 15 patients treated at a major pediatric oncology center from 1974 to 1991. The predominant underlying diagnosis was acute leukemia (lymphoblastic, n = 6; non-lymphoblastic, n = 2); two patients had chronic myeloid leukemia, two Hodgkin's disease, and three other solid tumors. Patients ranged from 7 to 27 years of age at diagnosis of this complication, with a median interval of 25 months (range, 0-11 years) from primary diagnosis. Both steroids and radiation therapy appear implicated in the pathogenesis of avascular necrosis: nine patients had received high cumulative doses of prednisone (3.4-14 g/m2), four had received 35-64.8 Gy local irradiation involving the femoral head, and one underwent total body irradiation (12 Gy). Of the 11 surviving patients, six are asymptomatic and fully active. Two patients have joint pain that is responsive to conservative measures. Severe pain and joint deterioration necessitated arthroplasty in two cases, and a third child is undergoing orthopedic evaluation because of worsening symptoms. Thus, like adult cancer patients, children who receive high doses of steroids or local irradiation involving femoral heads are at risk for avascular necrosis. In patients with chronic myeloid leukemia, the complication may be disease related. Although outcomes in our series are better than those reported in adults, the long period of risk for these children and young adults precludes definitive conclusions.