The Geometry Parameters Measurement in the Computer Aided Knee Replacement Surgery System

The accuracy of the low extremity mechanical axis alignment is an important factor in achieving successful knee replacement. And the geometry parameters, such as the distance between the femur condyle surface and tibia condyle surface, the angle between the cut plane in the femur and tibia condyle, the angle and distance between mechanical axis of the femur and tibia and so on, directly affect the low extremity mechanical axis alignment accuracy. In this paper, we reconstruct the three-dimensional femur and tibia model from their CT images by the Visualization Toolkits (VTK). And the geometry parameters of the knee joint, such as the distance of the tibia and femur epicondyles and so on, are calculated in the application software for computer aided knee replacement surgery.