Finite element analysis of muscle loading effect on biomechanics of early healing of femoral stem fractures

Cheng Chaoran; Zhang Junxia; Jia Jun

doi:10.12307/2025.814

Abstract：BACKGROUND:Previous studies have mostly performed biomechanical analysis of early fracture healing by ignoring muscle loading and using simplified femoral loading. Nevertheless,the biomechanical effects of muscle loading on early fracture healing are still uncertain. OBJECTIVE:To construct various femoral loading models allows for the study of the biomechanical effects of muscle loading on fracture healing,enabling clinicians to gain a deeper understanding of the biomechanical process of fracture healing and to optimize treatment protocols. METHODS:The AnyBody Modeling System software was employed to construct a personalized human musculoskeletal system,which was then analyzed by simulation in order to obtain the musculoskeletal loading model in vivo. This model,along with the femur loading model constructed using the improved simplified loading method and the simplified loading method,was utilized as boundary conditions for the finite element inputs,which were used to analyze the locking compression plate stress-strain and interfragmentary strain in the standing condition,respectively. RESULTS AND CONCLUSION:(1) The locking compression plate stresses and strains and interfragmentary strains obtained from the musculoskeletal method were,respectively,31.9％,38.9％,and 19.5％ smaller than those obtained from the simplified loading method. (2) A comparison of the musculoskeletal method with the modified simplified loading method revealed that the neglect of muscle loading resulted in an overestimation of locking compression plate stress and strain,as well as interfragmentary strain,by 16.8％,14.3％,and 19.5％,respectively. Muscle loading did not have a significant effect on the magnitude of the shear motion of the fracture block,whereas it did have a significant effect on the direction of motion. (3) The results indicated that the simplified femoral loading and the method of ignoring muscle loading exhibited some deviation from the musculoskeletal loading situation. Consequently,it is necessary to consider the biomechanical effects of muscle loading in the study of fracture healing.