Preliminary report on usefulness of magnetic resonance imaging for outcome prediction in early-stage Legg-Calvé-Perthes disease.

The usefulness of magnetic resonance imaging (MRI) for predicting prognosis was evaluated in 11 patients with unilateral early-stage Legg-Calvé-Perthes disease who were treated with a non-weight-bearing abduction brace. Six to 10 months after disease onset, severity of cartilage hypertrophy and physeal curvature of the femoral head were scored on MRI. Femoral head deformity was radiographically evaluated. Among five patients whose MRI score was 8 or greater, radiographic evaluation after the treatment was "poor" or "fair," whereas evaluation for the other six patients whose MRI score was 7 or less was "good." The MRI scores indicated possible occurrence of femoral head deformation. Treatment method should be considered carefully when the MRI score is high.