Topological Optimization Design for a Multiscale Femoral Prosthesis Model Based on Homogenization Method

Femur is a thigh bone in humans, which is particularly prone to injury and difficult to mend if damaged. The stress shielding effect is caused by a change in bone mechanics transmission route as a result of femur bone damage. The formation of a porous structure provides a better solution to the problem of stress shielding effect reduction. The porous material is basically a solid which has empty space(s) which is not covered by the primary structure of particles that build up the solid’s structure. Traditional porous materials have a uniform density distribution in their microstructure. The density distribution of a material should be established according to different loads in each location of the material to completely represent its characteristics. In this paper, to acquire the ideal density distribution of porous materials and construct high-performance variable-density porous structures, topological optimization is applied into the design of the lattice structure. According to a structure constructed utilising individualised parameters paired with computed tomography (CT) data of the human femur, a topological optimization design of a multiscale femoral prosthesis model based on the homogenization approach is presented. Experiments on different femoral prosthesis architectures revealed that variable-density porous prostheses have superior material and stress distributions than equal-density porous prostheses under the same stress and successfully decreased femoral stress shielding to improve prosthetic stability.