An Analysis of Reoperations Following Proximal Femoral Varus Derotational Osteotomy in Children with Cerebral Palsy.

Abstract

Hip displacement is common in children with cerebral palsy (CP). The existing literature has focused on native-hip longevity in patients with CP. This study investigated the reoperation-free rate of hips in children with CP following index proximal femoral varus derotational osteotomy (VDRO). We conducted a retrospective cohort study of patients with CP who were <18 years of age and underwent VDRO surgery at a tertiary referral center between January 2004 and January 2022, and who were followed for at least 2 years after the index surgery. Two hundred and eighty-nine patients (518 hips) met the inclusion criteria. Any return to the operating room for a same-site procedure counted as a reoperation, apart from elective hardware removal undertaken while the patient underwent a distinctly separate procedure. Reoperation rates and odds ratios (ORs) were calculated. Analyses were carried out using logistic regression and Cox proportional hazard models. We found a 29.2% rate of reoperation (151 reoperations among 518 hips). The reoperation rate was greatest for patients functioning at Gross Motor Function Classification System (GMFCS) level V (32.2% for level V, 27.8% for level IV, and 25.5% for level II/III), although the difference did not reach significance (p = 0.73). Hips in patients ≥6 years of age were significantly less likely to require reoperation than in those <6 years of age (23.1% versus 46.0%; p < 0.01). Bilateral index procedures (OR, 3.68 [95% confidence interval (CI), 1.68 to 8.04]; p < 0.01) significantly increased the risk of reoperation, regardless of operative side (31.1% right versus 32.3% left; p = 0.84). Additionally, operations on the left hip (OR, 1.24; 95% CI, 1.04 to 1.48; p = 0.02) had an increased risk of reoperation compared with those on the right. The frequency of reoperation in this large cohort was 29.2%, which is similar to previously published rates. An age of <6 years at the index surgery, operation on the left hip, and bilateral VDRO were the only significant risk factors for reoperation; however, there was a nonsignificant stepwise increase in the reoperation rate with increasing GMFCS level. These findings enhance a surgical team's ability to optimize counseling for families and patients with CP regarding the frequency and timing of additional hip surgery. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.