Fassier–Duval femoral rodding in children with osteogenesis imperfecta receiving bisphosphonates: functional outcomes at one year

Abstract

Purpose To examine the functional outcomes of children with osteogenesis imperfecta (OI) following initial Fassier–Duval (FD) rodding to the femur at 1 year, and to determine which factors are associated with change in gross motor function, ambulation, and functional performance. Methods Approval from our Institutional Review Board was obtained. A retrospective chart review identified 60 children (28 males, 32 females) with OI who underwent initial FD femoral rodding (101 rods) and who were receiving bisphosphonates. The mean age of the children was 3 years, 11 months at the initial femoral FD rodding. Two had type I OI, 30 type III, 27 type IV, and one type VI. The maximum length of follow-up was 4 years. Telescoping FD rods were used for the femurs, with surgeries performed one leg at a time, with a 1-week interval. The active range of motion (AROM) of the hips and knees in flexion was measured 4–5 weeks post-initial rodding. Outcomes on the Gillette Functional Assessment Questionnaire (FAQ) Ambulation Scale, the Gross Motor Function Measure (GMFM), and the Pediatric Evaluation of Disability Inventory (PEDI) were compared pre-operatively and at 1 year post-surgery using t-tests and multivariate linear regression. Results Pre-operatively, the mean FAQ score was 2.0, and this increased to 5.8 at 1 year post-surgery. Statistically significant improvements (P ≤ 0.05) were found on the FAQ, crawling, standing, walking and running, and total domains of the GMFM, and PEDI mobility and self-care from baseline to 1 year. The results from the multivariate linear regression indicate that older age (P = 0.0045) and higher weight (P = 0.0164) are significantly associated with lower scores in the self-care domain of the PEDI, and that OI type III compared to type IV is significantly associated (P = 0.0457) with greater improvement on the crawling domain of the GMFM. Higher weight was also associated (P = 0.0289) with lower scores in the standing domain of the GMFM, as well as with the total GMFM score (P = 0.0398). Conclusions Our findings indicate that initial FD femoral rodding resulted in benefits in ambulation, gross motor function, self-care, and mobility for children with OI beyond physiological expectations due to developmental growth. FD rodding is a procedure which can improve the overall mobility in children with OI with significant femoral deformities.