Ellipsoidal Process of the Femoral Head in Legg-Calvé-Perthes Disease: Effect of Prophylactic Hemiepiphysiodesis.

Purpose: Legg-Calvé-Perthes disease (LCPD) often causes the residual deformity, typically appearing as an ellipsoidal shape. In some cases, this ovalization is related to the asymmetric growth of the femoral head physis, which presents a growth-inhibiting necrotic area in the anterosuperior quadrant. The objective of the present study is to evaluate the effectiveness of selective hemiepiphysiodesis of the healthy physis in the posteroinferior quadrant as a means of disrupting femoral head ovalization in cases of LCPD with the previous onset of ovalization. Methods: We performed a prospective study of 39 LCPD hips operated on consecutively by selective hemiepiphysiodesis of the posteroinferior portion of the head during the reossification phase.Surgical indication was based on a progressive increase in the ellipsoidal index (EI), the presence of a double epiphyseal nucleus of reossification, physeal narrowing, and physeal angulation. Hemiepiphysiodesis was performed at the mean patient age of 8.8 years (SD 1.5) and a mean of 4.7 years (SD 1.4) following disease onset. Results: Preoperative EI was 1.80 (SD 0.2), which was reduced to 1.72 (SD 0.2) postoperatively ( Conclusion: As revealed by the EI, the ellipsoidal process may be stopped by selective hemiepiphysiodesis in the posteroinferior quadrant of the femoral head. Level of Evidence: II.