Abstract:Abstract: Objective To establish a finite element model of the proximal femur to analyze the risk of injury of the proximal femur under the conditions of optional speed and rapid rise during the initial stage of sitting-to-stand conversion. Methods The three-dimensional reconstruction and reverse modeling of the CT image of the proximal femur of the elderly complete the solid model. The finite element model is established through material assignment and meshing. Based on the finite element analysis software ANSYS, the boundary conditions are constrained, and loads of 1733N and 1837N are applied to obtain the stress distribution and strain data of the proximal femur at different rising speeds.Results The areas of stress concentration were both the medial edge of the greater trochanter and the femoral neck. The peak stress and micro-strain appear on the inner edge of the larger rotor. The peak stress is 30.16 MPa and the micro-strain peak is 2553.5 in the rapid standing situation; the peak of self-selected speed is lower, 28.69 MPa and 2430.4. For the stress concentration area of the femoral neck, the rapid rise stress range is 13.42MPa to 23.46MPa, and the self-selected speed rise stress range is 12.76MPa to 25.51MPa. Conclusions Frequent sit-to-stand transitions may increase the risk of fatigue fractures of the proximal femur in the elderly; rapid-to-stand transitions have a higher risk of injury to the proximal femur than the self-selected speed to stand-to-stand transitions.