The utility of additively manufactured β-Ti latticed hip implants in reducing femoral stress shielding: A finite element study.

Abstract

Total or partial hip replacement procedures have become one of the most frequently performed surgical procedures worldwide. However, a significant and increasing percentage of these patients return for revision surgeries due to stress shielding phenomena and the following implications such as aseptic implant loosening. Various strategies are under investigation to reduce the mechanical properties gap between the implant and the femur tissues. In this study, different development aspects have been merged to improve the design of hip implants and minimise the stress shielding. A low elastic modulus β-Ti TNTZO alloy has been used as the implant material. An actively optimised lattice structure has been embedded into the implant to tune its mechanical properties according to the bone properties of the patient. The study showed that using TNTZO reduced the average stress shielding of the implant by 31 % compared to commercial CoCr implants. Moreover, with two-step TNTZO lattice optimisation, the stress shielding was fully eliminated in all the femur sections, which accelerates the healing process of the bone and extends its long-term life. The study presented a scope for further optimisation to address other objectives, such as implant stiffness and eliminating stress concentration zones.