Dynamic behavior study of a transfemoral prosthesis user during three daily activities

Abstract

Lower limb amputations often result in significant biomechanical challenges, particularly at the interface between the residual limb and the prosthetic socket. Patients frequently report discomfort, pain, and skin irritation due to uneven load distribution and high stress concentrations, especially at the distal end of the femur. This study aims to improve the mechanical performance of the stump–prosthesis interface by introducing a structural implant at the end of the femoral bone. A finite element model was developed to simulate the biomechanical response of the residual limb– prosthesis system during three common daily activities: normal walking, stair descent, and stair ascent. The analysis focused on evaluating key mechanical indicators Von Mises stress, contact pressure (CPRESS), and longitudinal shear stress (CSHEAR1) across critical interfaces (stump–prosthesis, liner, and socket), comparing models with and without the implant. The results demonstrate that incorporating the implant significantly reduces peak stresses and improves stress distribution in all tested scenarios. The implant effectively disperses localized stress concentrations, lowers contact pressures and shear forces, and ensures that mechanical performance remains within clinically acceptable thresholds. These improvements suggest better protection of soft tissues, increased comfort, and a reduced risk of complications such as erythema and pressure ulcers. This study highlights the potential of implant-integrated prostheses to enhance user comfort, mobility, and quality of life. The findings offer a solid foundation for future innovations in prosthetic design and biomechanical optimization.