Femoral head osteonecrosis in pediatric and young adult patients with leukemia or lymphoma

Purpose Osteonecrosis of the capital femoral epiphysis is a significant late toxicity of treatment for childhood leukemia and lymphoma. We determined clinical and imaging risk factors predicting clinical joint outcomes of femoral head osteonecrosis in pediatric patients with leukemia or lymphoma. Patients and Methods We reviewed retrospectively medical records and magnetic resonance imaging scans of 80 patients with osteonecrosis of the capital femoral epiphysis. Logistic regression was used to examine relationships between risk factors and outcomes of joint surface collapse and arthroplasty. We used Kaplan-Meier survival curves to display the time to joint surface collapse and arthroplasty based on selected predictors. Results Median time between primary diagnosis and diagnosis of osteonecrosis of the hip was 1.7 years (range, 0.1 to 17.5 years). Twenty-three patients (29%) underwent arthroplasty in 36 hips at a mean of 1.3 years (range, 0.5 to 8.6 years) after diagnosis of osteonecrosis. Median age at time of first arthroplasty was 20.1 years (range, 15.1 to 35.4 years). Joint outcome of osteonecrosis was predicted solely by lesion size at diagnosis of osteonecrosis. The worst prognosis was associated with lesions occupying more than 30% of the femoral head volume; 80% of hips with these lesions collapsed within 2 years of diagnosis and 50% required arthroplasty. Conclusion Lesion size of osteonecrosis is the best predictor of clinical joint outcome of hip osteonecrosis in survivors of pediatric hematologic malignancy. Lesions occupying more than 30% of the femoral head have high likelihood of joint deterioration necessitating arthroplasty at a young age.