Growth Modulation to Improve Femoral Head Sphericity in Legg-Calvé-Perthes Disease.

Introduction: Legg-Calvé-Perthes disease (LCPD) often causes residual deformities, typically manifesting as an ellipsoidal femoral head shape. This condition arises from initial bone collapse and necrosis, inhibiting growth at the anterosuperior femoral head and resulting in asymmetric growth. The aim of this study is to assess the effectiveness of selective hemiepiphysiodesis in improving femoral head sphericity in patients with LCPD with previous onset of ovalization.

Methods: We compared 71 hips undergoing prophylactic selective hemiepiphysiodesis (surgical group) against 86 hips managed nonsurgically (control group). Radiographic evaluations were performed at 3 time points (3 y after disease onset, 5 y after disease onset, and skeletal maturity) to assess disease progression and intervention effects, measuring the ellipsoidal index (EI), the Reimer migration index (RMI), and the articulotrochanteric distance (ATD), with classifications according to the Herring scale and final sphericity assessments.

Results: Both cohorts were initially comparable in terms of age at onset, sex, and degree of deformity, showing similar EI, Herring classifications, and RMI (P>0.05). At T2, significant improvements were observed in the EI, RMI, and ATD in the surgical group compared with the control group. At skeletal maturity, the surgical group demonstrated significantly improved sphericity across all 3 indices (P<0.05), confirming the effectiveness of selective hemiepiphysiodesis in halting and partially reversing the ovalization process. The sphericity deviation score was significantly lower in the operated group (28±12) compared with the control group (43±28), the EI improved to 1.68±0.25 in the operated group from 2.11±0.33 in the controls, and the RMI showed a marked improvement (24.0±8.1) compared with controls (32.4±7.3).

Conclusions: Growth modulation by selective hemiepiphysiodesis effectively disrupts the progression of femoral head ovalization and enhances sphericity. This intervention presents a viable option for mitigating the ellipsoidal process in patients with LCPD, suggesting a significant potential to improve long-term outcomes by addressing early signs of deformity.

Level of evidence: Level III-retrospective cohort study.