Design and mechanical properties of the gradient porous femoral implant based on TPMS

Purpose This study aims to address the issue of inadequate biomechanical compatibility of traditional homogeneous porous femoral implants. Design/methodology/approach A design method of a gradient porous femoral implant based on triply periodic minimal surface (TPMS) is proposed. Firstly, three structures of P, D and G are constructed. By regulating the association model between the curvature parameters of TPMS and porosity, single-cell structures and bone scaffold models with different porosity are constructed. Then, the compression simulation and compression experiments are conducted on different porosity structures; the elastic modulus and yield strength data are obtained; and the mechanical properties of different structures are analyzed. Findings The quantitative relationship between porosity and yield strength is established. Based on this and the biomechanical requirements of the femur, a gradient distribution pattern of porosity along the z-axis of the implant is proposed. Finally, gradient porous femoral implants are designed and fabricated based on this relationship and the proposed gradient pattern, demonstrating the preliminary feasibility of the biomechanics-driven design methodology based on trend validation. Originality/value This work provides a theoretical basis and technical support for personalized implant design. The proposed method provides a quantitative design framework for creating functionally graded femoral implants based on TPMS structures, offering a potential solution to address the mechanical incompatibility of traditional homogeneous implants.