Biomechanical study of different fixation methods for posterior malleolus fracture.

In this study, the biomechanical effect of six fixation methods for the treatment of posterior malleolus fracture (PMF) were analyzed by finite element method. Fixation models include five different cannulated screw fixation models (0°, 5°, 10°, 15°, 20°) and a posterior plate fixation model. The von Mises stress (VMS) and displacement were used as criteria to evaluate the biomechanical efficiency of the different fixation models. The results demonstrated that the VMS and displacement will increase as the load increases. The buttress plate has better fixed strength and biomechanics results than screws. When the screw fixation angle is 15°, the model has better fixed strength and biomechanical stability than other screws fixation models. Therefore, we recommend the screws fixation with angle of 15° for posterior malleolus fracture, which can be used to guide clinical operation.