A computational optimisation study of hip implant using density mapping functionally graded biomimetic TPMS-based lattice structures

This study presents a computational framework for optimising a hip implant through a functionally graded biomimetic lattice structure, designed to reduce stress shielding. The optimisation technique, inspired by an inverse bone remodelling algorithm, promotes even stress distribution by reducing density and stiffness in regions with high strain energy compared to a reference level. The resulting non-uniform density distribution showed lower density levels along the implant stem's sides and higher density around its medial axis. This optimised material distribution was captured using mapping of a triply periodic minimal surface lattice structure on the implant, creating porous lattice surfaces within the solid structure. The porous implant's performance was evaluated using a finite element bone remodelling algorithm, comparing its bone response to a femur with a fully solid implant model, in terms of stress distribution and mass change. Results demonstrated improved bone formation at the bone-implant interface and enhanced stress transmission to the surrounding bone.