Abstract
PURPOSE: This biomechanical study aimed to investigate the effectiveness of a hinged elbow orthosis in reducing passive valgus forces following medial ulnar collateral ligament (UCL) injuries of the elbow joint. The hypothesis tested was that a hinged elbow orthosis reduces these passive valgus forces. METHODS: Eight fresh frozen cadaveric elbow specimens were prepared and tested under three scenarios: intact ligaments, simulated UCL rupture and application of a hinged elbow brace after simulated UCL rupture. Valgus instability was assessed using a custom testing set-up and the Optotrak motion capture system. Statistical analysis was conducted to compare the results across scenarios. RESULTS: Intraclass correlation (ICC) calculation showed that the testing set-up was reliable in investigating valgus deflection across all levels of applied force. The hinged elbow brace reduced passive valgus forces after UCL rupture. The reduction in valgus instability was consistent with close approximation to the native state, although not reaching its level. CONCLUSION: The hypothesis-that a hinged elbow orthosis significantly reduces passive valgus forces in the elbow following UCL injuries-is not supported by the data and therefore has to be rejected. Nevertheless, the study demonstrates a tendency that a hinged elbow brace could mitigate these forces, at least in an experimental cadaveric model with static study conditions. LEVEL OF EVIDENCE: The level of evidence of this study is level IV.