POSTERIOR STABILIZED AND CRUCIATE RETAINING KNEE PROSTHESES: COMPARISON OF IN VIVO 3D KINEMATICS USING FLUOROSCOPY

Accurate measurement of in vivo kinematics of total joint replacement is fundamental to improve prosthesis design and clinical outcome. In fluoroscopic analysis, the 3D relative pose of joint prosthesis components is reconstructed from the knowledge of the 3D geometry of each component and from a single plane projection. This is achieved with an accuracy of a few millimetres and a few degrees. Twenty-three patients with cruciate retaining and posterior stabilized prostheses were analyzed in order to assess the in vivo performance of the spine-cam mechanism. The posterior stabilized design exhibits a more physiological pattern of the anteroposterior motion of the condyles during flexion. This result is well-suited with the larger active knee flexion exhibited by the posterior stabilized knees.