Intra-operative measurement and real-time visualization of the articulation of replaced knee joint surfaces during total knee anthroplasty

This study aims at establishing a system capable of evaluating knee-joint kinematics during total knee arthroplasty (TKA). This enables one to optimize the implantation of the prosthesis and the level of the joint line, intraoperatively. To achieve this the authors combined two different types of data (6-DOF kinematic data of knee movement obtained by a photostereometric system and an accurate computer model of the joint surfaces) in order to compute the articulation of replaced joint surfaces. To visualize this time-varying intersurface relationship on a real-time basis, the authors employed a distance-map technique, capable of visualizing the proximity and contact of opposing surfaces. Through cadaveric experiments, the articulation was verified to be visualized by using a wireframe-based animation at a rate of 25 frames per second, and the distance map with a surface resolution of 1 mm was verified to be updated at a rate of 10 frames per second