Design and simulation of polymethyl methacrylate-titanium composite bone fixing plates using finite element analysis: Optimizing the composition to minimize the stress shielding effect

Abstract

Stress shielding is a mechanical phenomenon usually found in load-bearing bone implants. Difference in mechanical properties between the natural bone and the artificial implant leads to stress shielding problem. In the present work, polymethyl methacrylate and commercial pure titanium were selected to design laminate and particulate composites. Optimum composition was theoretically obtained that exhibits mechanical properties close to that of natural human bone. Bone fixing plate was designed for femur bone using computer-aided design. Finite element analysis was adopted to analyze the stress distribution in the bone and implant under static load conditions. Fixing plate with three screws was modeled and simulated using finite element analysis to investigate the stress distribution. Simulation was also done considering 316 L stainless steel as fixing implant and compared with the present optimized composition. Laminate composite with 0.3 volume fraction of titanium has shown mechanical properties close to the bone compared with other combinations. The results have clearly shown that the von-Mises stress induced in the bone with polymethyl methacrylate-titanium laminate composite plates was increased compared with the bone implanted with 316 L steel. Interestingly, laminate composites exhibited higher stresses in the bone compared with particulate composites. From the present design and simulation, it is clearly demonstrated that the laminate composites of polymethyl methacrylate–30% titanium can be an optimum choice for load-bearing implant materials with reduced stress shielding effect.