Novel Process for Designing Topology Optimized Femoral Stems Printable by Metal Additive Manufacturing

Abstract

Total hip arthroplasty faces an issue of the high cost and risks of revision surgeries. Studies show that more than 50% of the revision surgeries are the consequence of the aseptic loosening of the implant. The cause of the loosening is the bone resorption during the bone remodeling due to poor load transfer to the bone because of the stiff metal used for the implant. The aim of this work is illustrating a novel process of designing topology optimized femoral stems printable by additive manufacturing to increase the load transfer. The proposed manual penalization process is used to produce the required stems followed by a multiple simulations process to select the optimum stem extraction iso-surface threshold value. The results show printable stems that increased the strain energy in the bone by 20% and had better micromotions uniform distribution resulting in more uniform bone growth.