Effect of greater trochanteric epiphysiodesis after femoral varus osteotomy for lateral pillar classification B and B/C border Legg–Calvé–Perthes disease

This is a retrospective observational study. Greater trochanteric epiphysiodesis (GTE) has been recommended to prevent Trendelenburg gait and limitation of the hip joint motion due to trochanteric overgrowth after femoral varus osteotomy (FVO) in Legg-Calvé-Perthes disease (LCPD). However, capital femoral physeal arrest frequently occurs in patients with severe disease (lateral pillar C), so GTE might not be as effective in these patients. The aim of this study was to compare trochanteric growth inhibition due to GTE after FVO between 2 age groups (<8 or >8 years) in patients with lateral pillar B and B/C border LCPD and evaluate the effectiveness of GTE compared with the normal, unaffected hip.This study included 19 children with lateral pillar B and B/C border LCPD in 1 leg who underwent FVO followed by GTE. Of the 19 children, 9 underwent GTE before the age of 8 years and 10 underwent GTE after 8 years of age. On radiographs taken at the immediate postoperative period and at skeletal maturity, the articulo-trochanteric distance (ATD), center-trochanteric distance (CTD), and neck-shaft angle (NSA) were compared between the 2 age groups. The amount of correction was compared between groups. The contralateral, unaffected hip was used as a control for trochanteric growth. The patients were clinically evaluated with Iowa hip score at the final follow-up.There was no significant difference between the 2 age groups in terms of time to GTE, length of follow-up, or lateral pillar classification. In the affected hip, the amount of correction of the ATD, CTD, and NSA was significantly greater in patients < 8 years than in patients > 8 years. However, in the unaffected hip, the change in the ATD, CTD, and NSA did not differ significantly between the 2 groups.We suggest that FVO followed by GTE for lateral pillar B and B/C border LCPD in patients under the age of 8 years can affect growth of the greater trochanter. However, effective growth inhibition due to GTE was not achieved after 8 years of age.