Radiographic and functional outcomes of shelf acetabuloplasty versus conservative management in legg-calvé-perthes disease: an age- and gender-matched study including healthy controls for isokinetic hip muscle strength

Abstract

Introduction: Shelf acetabuloplasty, one of surgical containment methods, have been employed to preserve hip joint congruity in the management of Legg-Calvé-Perthes disease (LCPD). However, its long-term effect on radiographic and functional outcomes remains unclear due to limited evidence. Moreover, comparative studies against conservative treatment are lacking. This study aimed to (1) compare the mid- to long-term outcomes between children with advanced-stage LCPD treated with shelf acetabuloplasty and those receiving conservative management, and (2) evaluate isokinetic hip muscle strength compared to age- and gender-matched healthy controls.

Materials and methods: This retrospective age- and gender-matched study included 28 children with unilateral LCPD, divided into Shelf (n = 14) and Conservative (n = 14) treatment groups. A healthy control group (n = 14) was also recruited for isokinetic comparisons. Radiographic outcomes were assessed using modified Stulberg classification and several quantitative parameters. Functional outcomes were assessed using the Harris Hip Score (HHS) and isokinetic testing of hip muscle strength.

Results: The Shelf group (median follow-up: 5.5 years, IQR: 4-7) showed significantly better HHS (67.9 ± 15.9) compared to the Conservative group (median follow-up: 6 years, IQR: 5-8) (54.6 ± 13.3; p = 0.024) at the final follow-up. Shelf acetabuloplasty also resulted in significantly improved radiographic parameters, including centre-edge angle (p < 0.001) and femoral head coverage (p = 0.002). Isokinetic testing revealed that the Conservative group had significantly lower hip extension (p = 0.021), abduction (p = 0.018), and adduction (p = 0.027) torque values, as well as greater muscle fatigue (p = 0.014). In contrast, the Shelf and Control groups exhibited comparable performance in most strength and endurance parameters.

Conclusions: Shelf acetabuloplasty, when applied as a salvage procedure in advanced-stage LCPD, may provide better functional outcomes and improved hip muscle performance compared to conservative treatment, despite comparable long-term femoral head morphology. Following Shelf acetabuloplasty, comparable hip flexor and extensor strength to healthy controls can be expected, although mild abductor and adductor weakness may persist.

Keywords: Conservative treatment; Isokinetic muscle strength; Legg-calvé-perthes disease; Radiographic outcomes; Salvage procedure; Shelf acetabuloplasty.