Finite Element Analysis of 3D-Printed Implants in Knee Replacements

Additive manufacturing is a constantly developing field that has proved to have many benefits in biomedical applications, some of which have even been cleared by the FDA, from screws and surgical tools to dental and orthopedic implants. Additive manufacturing is such an attractive option for creating implants because of the customizable aspects, allowing for patient specific prosthesis. The use of additive manufacturing in knee replacements is a subject that can greatly benefit the long-term comfort and success of implants. Total knee arthroplasty, TKA, occurs when there is damage to the knee joint that cannot be helped through any other means, like medicine or physical therapy. TKA is a major surgery that replaces the ends of the femur and tibia in the tibiofemoral joint. At the moment, most implants are pre-fabricated to different sizes, so when being used on the patient it is up to the surgeon's knowledge of how much of the bone to cut, shave, and drill in order to achieve an optimal fit. Using 3D printing to fabricate knee implants that are patient-specific is something that could improve the comfort and quality of life of people who require this surgery. Using additive manufacturing and finite element analysis in the process would allow for an implant that is created to fit the patient specifically, so there is less damage done to the bones, and less approximation in the middle of the operation. In this study, simulations were performed to predict the distortions and residual stresses that arise from additive manufacturing, which was then used to evaluate the performance of the implant under typical conditions. These results allow for a thorough understanding of how the knee would behave at each position along with the stresses that would come from the loading. The study will evaluate the resultant stresses that come from loading along with the part distortions and residual stresses created by the additive manufacturing process. Finally, parametric studies will be conducted to show a viable option for the 3D printed implant, and how the design may be improved along with additive manufacturing process planning for optimal performance.