Analysis of modified surface topographies of titanium-based hip implants using finite element method.

BACKGROUND: In order to ensure the proper function of the cementless hip implant, the connection between the femoral bone and the implant has to be as strong as possible. According to experimental studies, implants with a rough surface reduce micro-movements between femoral bone and implant, which helps form a stronger connection between them. OBJECTIVE: The goal of this study was to analyze how half-cylinder surface topographies of different diameter values affect shear stress values and their distribution on the surface of the hip implant and trabecular femoral bone. METHODS: Nine models with different half-cylinder diameter values (200 µm, 400 µm, and 500 µm) and distances between half-cylinders were created for the analysis using the finite element method. Each model consisted of three layers: implant, trabecular, and cortical femoral bone. RESULTS: For all three diameter values, the highest shear stress value, for the implant layer, was located after the first half-cylinder on the side where force was defined. For the trabecular bone, the first half-cylinder was under lower amounts of shear stress. CONCLUSION: If we only consider shear stress values, we can say that models with 400 µm and 500 µm diameter values are a better choice than models with 100 µm diameter values.