Finite element study for intra and postarthroplastic evaluation of ligament balancing in standing position using instrumented tibial baseplate

To obtain a long lifespan of knee joint implant, it is indispensable to balance the collateral ligaments of the knee and to restore a correct alignment of the mechanical axis of the lower limb during total knee replacement (TKR). Nowadays, a proper mechanical axis alignment of the lower limb is guaranteed by computer assisted orthopaedic surgery (CAOS). To assure a symmetric laxity of these ligaments, a smart tibial baseplate instrumented with three strain gages could be used. Our objective is to study the displacement of the pressure center as a function of ligament balancing represented by the shift of resultant axial force exerted by the two condyles of the femoral component on the tibial tray. Improving the surgeon perception helps to solve the ligament balancing problem. Our first instrumented tibial baseplate has been modeled using ANSYS Workbench 11. As a result, soft tissue balance is possible to be assessed using the pressure center position. In this paper, we present our approach and the preliminary results of instrumented tibial plateau model which would be validated later by the first prototype.