Application of Topology Optimization in Design of Stem Profile in Hip Implants using Finite Element Method

Appropriate design of stem shape is an important factor in total hip replacement. It affects the attachment of the implant to the bone and the stability of the implant. Using topology optimization, this study has been an attempt to propose an optimized model of the stem profile of the hip implants. In this regard, a three-dimensional finite element model of the implant has been combined with a stiffness-based topology optimization algorithm to reduce the relative motion between the implant and the bone. The objective function in the optimization problem is the compliance of the structure which should be minimized. Also, a constraint on usable volume is applied to the structure. Then smoothing process has been done on the optimal model to prevent its geometric complexities. Results show that the final model has a smaller weight, less displacement, and more uniform stress distribution. In addition, using conventional production methods, this model can be easily produced.