Figure 1.

Picture of the knee simulator. The system is able to simulate a continuous weight-bearing knee flexion while moving the vertical frame and adjusting the muscle loads according to a predefined constant force measured by an uni-axial load cell in the ankle assembly simultaneously. Femoral and tibial shafts were secured into thick-walled aluminum adapter cylinders, and the adapter cylinders were attached to the fixation cylinders of the hip and angle assemblies via accurately-positioned screws. The kinematics of the knee joint was measured using ZEBRIS^® ultrasonic motion capture marker triads attaching on the tibial and femoral fixation tubes. Sketched arrows show the orientation of the coordinate systems in the knee joint