Combined pelvic osteotomy and proximal femoral-guided growth in children with cerebral palsy and hip displacement.

AIM: To evaluate radiographic outcomes after combined pelvic osteotomy and proximal femoral-guided growth in children with cerebral palsy (CP) and hip displacement. METHOD: We retrospectively reviewed 32 children (14 males, 18 females) with CP (51 hips) treated with combined pelvic osteotomy and guided growth between 2016 and 2022. Indications were a migration percentage greater than 40%, a head-shaft angle (HSA) greater than 155°, and an acetabular index (≥ 22°). Mean age at surgery was 6 years (range 4-8 years 6 months) with a minimum 2-year follow-up. Gross Motor Function Classification System (GMFCS) levels were: seven in GMFCS level III, 20 in GMFCS level IV, and five in GMFCS level V. Radiographic parameters were assessed serially. Poor outcome was defined as a migration percentage of 50% or greater at the final review. RESULTS: HSA, acetabular index, and migration percentage improved significantly (-9.5°, -7.2°, -28%; all p < 0.001). Generalized estimating equation models showed progressive decreases in HSA with the follow-up (-2.9° per interval, p < 0.001) and lower HSA in older children (-3° per year, p < 0.001). The acetabular index showed an early postoperative reduction with smaller longitudinal changes and was higher in children with greater motor impairment (+3.6° per GMFCS level, p = 0.003). The migration percentage improved markedly and continued to decline with the follow-up (-6% per interval, p < 0.001), but was significantly higher in children classified in higher GMFCS levels (+9.9% per level, p = 0.001). Five hips (9%) had poor outcomes, mostly with a baseline migration percentage of 80% or greater. INTERPRETATION: While favourable outcomes were generally observed in hips with moderate displacement (approximate migration percentage 40%-60%), those with more severe displacement (e.g. a migration percentage of 80% or more) demonstrated less consistent correction and may ultimately require additional reconstruction.