Advancing TKA Biomechanics: From Joint Simulator to Boundary Condition Development

This dissertation addresses four specific aims that collectively attempted to advance the experimental and computational analysis of total knee arthroplasty (TKA) components. The first study focused on the development of a novel whole knee joint simulator capable of simultaneous tibiofemoral and patellofemoral knee loading. This simulator employs custom fixturing to facilitate dynamic, unconstrained, muscle-driven PF articulation alongside controlled TF contact mechanics. Validation against experimental measurements showed strong agreement, demonstrating the simulator's potential as a valuable tool for future TKA design and surgical technique investigations. The second study verified implant-specific physiological boundary conditions which accurately simulate activities of daily living using in vivo fluoroscopic knee kinematics. This approach successfully recreated activities of daily living such as Gait, Stair Descent, and Sit-Stand, providing robust conditions for preclinical TKA testing. The third study investigated the performance of a novel TKA insert and its ability to restore more natural knee kinematics. Cadaveric simulations revealed that the medial-stabilized design, featuring increased medial conformity, resulted in reduced anterior-posterior (A-P) translations and more natural knee rotations compared to a symmetric insert design. These findings underscore the critical role of implant conformity in achieving knee stability post-TKA. The final study explored using retrieved tibial insert components to verify the previously developed knee loading boundary conditions and to validate an accompanying finite element (FE) model. The FE models predict contact area and pressure distributions in addition to knee kinematics. This methodology proved to be successful in assessing the validity of experimental boundary conditions to provide more accurate simulations for the pre-clinical development of TKA implants. Together, these aims form a comprehensive approach to advancing TKA biomechanics, from innovative joint simulator development and physiologically relevant boundary conditions to the evaluation of novel implant designs and computational wear validation. This work contributes to the ongoing effort to improve TKA outcomes and patient quality of life through rigorous experimental and computational methodologies.