This study analyzes the biomechanical stability of different internal fixation strategies for distal humerus C-type fractures using advanced musculoskeletal dynamics and finite element modeling. Researchers used CT images from a healthy adult to create a 3D anatomical model processed through AnyBody, a musculoskeletal simulation platform, and Abaqus, a finite element analysis program. Elbow flexion and extension from 0° to 130° across parallel, posterolateral, and posteromedial plate configurations were simulated to evaluate interfragmentary micromotion (IFM), stress distribution, and load response. The simulations demonstrated increased IFM with greater flexion angles and showed that IFM was highly dependent on plate configuration. Parallel plate fixation maintained IFM within the optimal healing range (0.06–0.20 mm) up to 80° of flexion, while vertical configurations exceeded this range beyond 30°. In terms of stress distribution, the analysis showed an angle-dependent migration of stress from the falciform fossa to the distal lateral condyle, marking it as a biomechanical weak point due to lower bone density and cortical thickness. Load response analysis confirmed that parallel plates provided increased axial stiffness across the full range of motion. The results were consistent with known anatomical data, confirming the validity of the simulation. The study concluded that dynamic musculoskeletal analysis provides an accurate reference for improving plate configuration selection and determining safe ranges of postoperative joint movement.