IN VIVO THREE-DIMENSIONAL KINEMATICS OF TOTAL KNEE REPLACEMENTS DURING OPEN AND CLOSED KINETIC CHAIN ACTIVITIES

Abstract

Measurement of the three-dimensional (3D) motions and surface kinematics of total knee replacements (TKR) during different kinetic activities helps provide necessary knowledge for a better use of these activities for rehabilitation purposes. The 3D kinematics of the knee in eight patients with posterior cruciate ligament-retaining (PCL-retaining) mobile-bearing TKR were measured during sit-to-stand, a closed kinetic chain (CKC) activity, and active knee flexion/extension, an open kinetic chain (OKC) activity, using a single-plane, 3D fluoroscopy method. Angular, translational motions as well as the contact patterns of the prosthesis components were calculated. The joint angular motion patterns were not statistically different between the OKC and CKC activities, but different contact patterns were found. The knee joint center translated more anteriorly during OKC than during CKC activities. Compared to the CKC activity, the more anterior contact positions and smaller total displacements of the medial contact in the OKC activity may indicate a greater loading in PCL and a smaller contact area on the medial tibial plateau. Rehabilitation of patients with mobile-bearing TKR may have to consider the potential negative effects of the greater loadings in the PCL and greater stresses in the medial tibial plateau when using OKC as a training exercise.