Functional Comparison of a Pediatric Patient With Osteosarcoma and Limb-Sparing Distal Femoral Endoprosthesis With an Identical Twin

Abstract

Background/Objective: In children, limb salvage techniques have been more slowly adopted because of concerns of complications from multiple surgical procedures, the sacrificing of the physis, and the leg-length discrepancy that can ensue. The purpose of this study was to compare gait and function between a pediatric patient with a distal femur replacement and his identical, healthy twin brother. Methods: Design: A single, case-control design was used. Participants: A 13-year-old adolescent boy underwent a distal femoral resection and endoprosthetic reconstruction with a noninvasive extendible endoprosthesis. The control was the healthy, identical twin brother of the case patient. Main Outcome Measure(s): Functional movement testing consisting of 5× Sit-to-Stand Test, 10-m Walk Test, Timed Up and Go (TUG) test, and L-test. Spatiotemporal gait analysis was used to assess degree of asymmetry. Results: Comparisons were mixed across the functional movement testing, with the patient performing inferiorly on the 5× Sit-to-Stand Test and the 10-m Walk Test and superiorly on the TUG test and the L-test. Degree of asymmetry for step time, swing time, single support, and initial double support were all significantly different (P ≤ .05), with the patient being less symmetric in all measures. Limitations: This study is limited by its small sample size and a comparison with a single time point. Conclusion: Although the patient is doing well functionally, asymmetries remain compared with his twin. Future research should focus on more direct comparison of subjects who have undergone different treatment options for sarcoma.