Biomechanical analysis of elastic fixation for lisfranc injuries with finite elements method

Lisfranc injury is a complex trauma involving the midfoot joint, and treatment options range from conservative management to surgical intervention. Elastic fixation, an innovative surgical technique, has garnered attention for its ability to preserve the foot's biomechanical properties. However, the influence of pretension on the efficacy of elastic fixation remains unclear. This study aims to use three - dimensional (3D) finite element analysis (FEA) to examine the biomechanics of the Lisfranc joint under different pretension fixation states. It seeks to determine the optimal pretension for achieving the same biomechanical stability as normal ligaments. This will provide theoretical support for elastic fixation in treating Lisfranc injuries. The study analyzed stress distribution, von Mises stress, and displacement under different pretensions to assess the biomechanical stability of elastic fixation. Results showed that varying pretension levels differentially affected Lisfranc joint biomechanics. Specifically, increased pretension correlated with greater medial cuneiform-second metatarsal (MC1-MT2) joint space displacement and higher stress on the MC1, MT2, titanium plate, and tarsometatarsal joint cartilage. Nonetheless, each pretension level exhibited a unique stress distribution pattern. At 70 N of pretension, elastic fixation achieved biomechanical stability comparable to that of the normal foot model. This study demonstrates that elastic fixation can effectively restrict abnormal movements in the injured Lisfranc joint and identifies the optimal pretension for proper fixation.