Background: Femoral varus osteotomy (FVO) is a common treatment for Legg-Calve-Perthes disease (LCPD). Due to concerns of decreased hip abductor strength, neck-shaft angle (NSA), and articular-trochanteric distance (ATD), concomitant greater trochanteric apophysiodesis (GTA) is often performed. While abductor strength remains a concern, no studies have quantified hip strength following FVO+GTA. The purpose of this study was to objectively quantify hip strength in patients treated with FVO+GTA using isokinetic testing and analyze contributors to abductor weakness. Methods: A retrospective review was conducted for 26 patients who underwent unilateral FVO+GTA at Waldenström stages 1b-3a, and hip strength testing in stages 3b-4 using an isokinetic dynamometer. The strength of the operated side was compared with the contralateral side. Clinically significant abductor weakness between the contralateral and operated side was set at ≥25% based on previous data. Results: The mean age at diagnosis was 7.7±1.2 years (range: 5.9 to 9.6) and the time from surgery to testing was 3.3±1.3 years (range: 1.8 to 6.1). While the operated side showed significant decreases in NSA ( P <0.001) and ATD ( P =0.002) compared with the contralateral side, no significant difference in the abduction strength between sides was observed with a paired t test ( P =0.15). However, when patients were grouped by those who did only home exercises (n=11, 42%) versus outpatient physiotherapy (n=15, 58%), the home exercise group showed significantly weaker abduction strength on the operated side compared with the contralateral side with a paired t test ( P =0.027), whereas the outpatient physiotherapy group was insignificant ( P =0.93). In addition, all 4 patients who had abductor weakness ≥25% on the operated side were in the home exercise group. Conclusions: Following FVO+GTA, only 4 out of 26 patients (15%) had clinically significant abductor weakness, all of whom did only home exercises. We recommend outpatient physiotherapy after FVO+GTA to obtain more symmetrical abduction strength. Level of Evidence: Level III.
Carter et al. (Fri,) studied this question.