The influence of the screw configuration of the distal fibular plate on the biomechanics of lateral malleolar oblique fractures.

To investigate the influence of screw configuration of the distal fibular plate on the biomechanical effects of lateral malleolar oblique fractures. In this paper, multiple models were established using Computed Tomography (CT) data. Finite element analysis (FEA) was employed to compare the biomechanical characteristics (fracture-site displacement, fibular von Mises stress, and internal implant von Mises stress) of four internal fixation methods under different loading conditions (350N and 700N) and physiological conditions (20° dorsiflexion, 10° dorsiflexion, neutral, 10° plantarflexion, and 20° plantarflexion). In vitro experiments were performed for validation, and the results agreed well with the FEA predictions. The results indicated that the distal fibular plate with six screws yielded lower peak values of fracture-site displacement as well as lower peak fibular and internal implant von Mises stresses. Across physiological conditions, the lowest peak fracture-site displacement and the lowest peak fibular and internal implant von Mises stresses consistently occurred at 20° dorsiflexion. Moreover, all fixation configurations exhibited higher stability in dorsiflexion than in the neutral and plantarflexion positions. Overall, this study characterizes the stability and mechanical safety of distal fibular plate fixation under different physiological conditions during simulated daily standing, and may provide biomechanical evidence to support clinical fixation selection and postoperative rehabilitation planning for lateral malleolar fractures.