Does Remodeling of Distal Femoral Extension Osteotomy Cause Recurrence of Knee Flexion Deformity in Children With Cerebral Palsy?

Abstract

Distal femoral extension osteotomy (DFEO) is an established surgical option for correcting knee flexion deformity (KFD) in children with cerebral palsy. However, the extension deformity created at the distal femur may remodel over time, raising concerns about the recurrence of KFD. To quantify the extent and rate of posterior distal femoral angle (PDFA) remodeling after DFEO, identify contributing factors, and assess its correlation with recurrence of KFD. This retrospective study analyzed 54 children (102 knees) with spastic diplegic cerebral palsy who underwent DFEO between 2015 and 2022. Radiographic PDFA measurements and clinical KFD assessments were evaluated over a mean follow-up of 46.4 months. Statistical analyses included univariate, multivariate, and nested case-control models. The mean PDFA decreased from 118.3 degrees postoperatively to 100.9 degrees at 3 years, indicating 64.4% remodelling. Younger age (≤12 y) and the magnitude of correction (>25 degrees) were significant predictors of remodeling (P<0.05). Recurrence of KFD occurred in 18 knees (17.6%), but no significant correlation was found between remodeling and recurrence. GMFCS level was not a statistically significant factor for remodeling. Remodeling of the distal femur following DFEO does occur, especially in younger children and in those who underwent a larger degree of correction, but does not correlate with recurrence of KFD. DFEO remains a safe and effective intervention for flexed knee gait in cerebral palsy, with remodeling unlikely to compromise short-term outcomes. Level III.