Prevalence of osteonecrosis and associated risk factors in children before allogeneic BMT

Osteonecrosis (ON) is a debilitating long-term complication of allogeneic BMT (allo-BMT), but may begin before allo-BMT in some children because of their primary disease treatment. Therefore, to estimate the prevalence and associated risk factors for ON before allo-BMT, we conducted a retrospective analysis of magnetic resonance (MR) studies of 118 children who underwent first allo-BMT at our institution between December 2000 and September 2007. Of the 118 consecutive patients, 107 (90.7%) underwent prospective MR studies irrespective of symptoms (69 males; median age at allo-BMT 12.9 years), and 11 underwent MR studies for symptoms. Among the 107 who had prospective imaging, 23 (21.5%) had ON; nearly 50% had at least 30% epiphyseal involvement. Knees were more frequently involved than were hips; severity of ON was greater in hips. ON prevalence before allo-BMT was 23.72% when all 118 patients were included in the denominator. Risk factor analysis, limited to MR studies performed irrespective of symptoms, revealed female gender (P=0.049) and age 10 years at the time of MR study (P=0.03) as significant risk factors, and primary diagnosis of lymphoid malignancies and aplastic anemia trended toward significance. ON before allo-BMT is a common occurrence in children.