Defining Postoperative Weight Trends in Pediatric Patients Undergoing Limb Reconstruction Surgery by Distraction Osteogenesis

Background: Distraction osteogenesis (DO) is widely used to treat limb length discrepancy, deformity, and segmental defects. During recovery, body weight may change due to surgical stress, increased osteogenic metabolic demand, pain, reduced mobility, appetite changes, and disuse-related muscle loss. Because early weight change may affect wound healing, infection risk, and regeneration quality, defining postoperative weight trajectories is clinically relevant. We aimed to characterize early weight change after DO-based limb reconstruction and determine when deviation from baseline is greatest. Methods: We performed a single-center retrospective review of major limb reconstruction procedures performed between January 1, 2016, and December 31, 2022, with at least 1 year of follow-up. Demographics, treatment group, implant type, healing milestones, and serial weights were collected. Percent change in body weight from baseline during the first 84 postoperative days was analyzed with linear mixed-effects regression using a quadratic time term and patient-specific random intercepts and slopes. Timing and magnitude of the nadir were estimated with 95% CIs. Results: A total of 175 patients across 4 treatment groups: (1) external fixation for deformity correction alone; (2) external fixation for limb length discrepancy equalization; (3) extramedullary lengthening; and (4) intramedullary lengthening, contributed 1066 postoperative weight measurements (mean: 6.1 per patient). Weight status was similar immediately after surgery. Over 12 weeks, intramedullary lengthening showed the clearest U-shaped trajectory, with weight reaching a nadir of ∼2% below baseline at about 6 weeks (45 d), followed by gradual recovery. Across the 3 lengthening cohorts, early weight loss was consistently associated with higher Bone Healing Index/External Fixation Index (BHI/EFI), suggesting slower healing, although these differences were not statistically significant. Conclusions: Postoperative weight trajectories after DO vary by treatment group. Intramedullary lengthening showed the most pronounced early decline, followed by recovery. Early weight loss also showed a consistent, though nonsignificant, association with higher BHI/EFI. Level of Evidence: Level III—retrospective comparative study.