Development of a Workflow for Wear And Functional Simulation of Total Knee Replacements

Stoltze, Jonas Stensgaard

4. term

Design of Mechanical Systems, Master

2014

2014-06-03

This project deals with development of a workflow for wear and functional simulation of total knee replacement (TKR). All loads and driven motion of the knee joint are computed in the muscoloskeletal modelling program AnyBodyTM during a gait cycle, and through MATLAB applied to an FE model solved in FEBio. This model, containing tibial implant, femoral implant and the major surrounding ligaments, is solved with boundary conditions in all six degrees of freedom. The FE analysis predicts the kinematics and internal contact of the joint, of which the former is compared to fluoroscopic data and the AnyBody model. This showed good agreement in the translation directions, but the agreement of the rotations varied. The linear wear is estimated from the computed contact pressure with a developed algorithm written in MATLAB, which is verified with experimental results reported in the literature. The algorithm predicted a very low maximum wear depth (76.3 % deviation), compared to the literature, but the wear contour was in good agreement. The MS model can solve both an idealised hinge constrained model and a contact-based knee joint model, and in this project the wear during a gait cycle is investigated for both methods to investigate the difference in wear depth. The latter method uses the force-dependent kinematic solver, and this method turned out to predict the highest wear depth of the two methods.

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