Biomechanical Evaluation of Rotational Ankle Injuries: Validating a Computer Model Using Robotic Cadaveric Testing

Research Type: Level 5 - Case report, Expert opinion, Personal observation Introduction/Purpose: Deltoid ligament injuries occur in predefined sequences during rotational ankle fractures, but current knowledge about these sequences may be inaccurate. Computer modeling provides a novel approach to evaluate ligament behavior under rotational injury mechanisms. Methods: A biomechanical computer simulation model was developed using the AnyBody Modeling Software to evaluate ligament strain in rotational ankle injuries. Experimental data from a cadaveric study involving 18 human ankle specimens subjected to various loading conditions were used to optimize the computer model. Having optimized the computer model with uninjured cadaveric data, we simulated Supination-External Rotation (SER) stage 2-4b injuries by removing corresponding ligaments. Validation was done by comparing computer model predictions against the biomechanical experimental data. Results: The computer model replicated experimental findings, with correlation coefficients ranging from 0.81 to 0.99 across all injury stages and loading conditions. Furthermore, tension in the deep posterior tibiotalar ligament (DPTTL) increased progressively from SER2 to SER4a but remained unchanged in the SER2 phase. The model successfully captured progressive ligament strain and medial clear space changes during injury progression. Conclusion: This study introduces and validates a biomechanical simulation model for rotational ankle injuries. It offers a novel tool for exploring ligament biomechanics and injury mechanisms. The medial sagittal view of the computer model with the ligaments specified. The medial sagittal view of the computer model with the ligaments specified. Deltoid ligament sections are shown with black arrows, while other ligaments are shown with blue arrows. The deep deltoid sections are also shown with solid arrows and depicted as red. Note that the tibiofibular syndesmosis ligaments were hidden for the sake of visibility.