Our group tested two different types of liner used in a Total Knee Arthroplasty, which is the complete replacement of the knee joint. One is the PLI, a relatively flat liner that was designed for situations in which the PCL is functionally intact. The other liner is the CVD, a more curve liner designed to provide greater conformity. We also wanted to quantify femoral rollback in the knee.
Femoral rollback is the posterior translation of the femur on the tibia during flexion.
We tested the knee under a variety of loads. We applied a 134 N compressive load as well as varus and valgus moments to obtain data on the knee kinematics. The UFS system provided us with enough data to calculate the screw axis of the knee as it moves from flexion to extension. The screw axis is basically the axis about which the knee rotates. The axis moves as the knee moves along its path.