Evaluation of internal fixation stability of distal humerus C-type fractures based on musculoskeletal dynamics: finite element analysis under dynamic loading

In this study, we quantified the mechanical effect of muscle contraction force on the stability of internal fixation of distal humerus C-type fracture and revealed the biomechanical law in the postoperative period; we established a simulation model of dynamic and static loading and proposed a 'safe activity window' for postoperative exercise, which confirms the high stiffness of the parallel steel plate and the control of the angle of early active activity (≤ 80° of flexion). Flexion of more than 30° in the case of vertical plates leads to shear micromotion overruns (> 0.48 mm).