Three-dimensional finite element analyses of functionally graded femoral prostheses with different geometrical configurations

In this work, functionally graded femoral prostheses (FGFPs) with different geometrical configurations are studied using three-dimensional finite element analysis. The FGFP consists of stainless steel-hydroxyapatite (SS 316L-HA) and titanium alloy-hydroxyapatite (Ti-HA) with various volume fraction gradient exponents n=0.0, 0.1, 0.5, and 1.0. This study is the first to consider an FGFP with a combination of different profiles and cross-sections in a non-bonded implant-bone interface. The results show that the strain energy density in the proximal metaphysis of the femur increases by more than 22% in the FGFP with different geometrical configurations, which correspond to a reduction in stress shielding and subsequently decrease bone resorption. Simultaneously, the interface stresses in the bone-implant contact region have limited variations for all combinations of profiles and cross-sections. Therefore, FGFP can be employed to introduce a new optimum design for femoral prosthesis with adjustable stiffness, which can decrease stress shielding and interface stress. This condition results in an increase in the total lifespan of the hip replacement.