Clinical Results and In Vivo Kinematics Analysis of Osteonics Total Knee Arthroplasty

Abstract

The design characteristic of the Osteonics total knee is the high conformity of tibiofemoral articulation on the coronal plane. Primary total knee arthroplasty using Osteonics (Omnifit/Deltafit) total knee system was performed in 56 patients (78 knees). Of these, 45 patients (58 knees) were evaluated at least 5 years. The varus-valgus stress test was performed at 20° of knee flexion using a digital instrument. In 40 patients (50 knees), we measured the tibiofemoral contact point on the sagittal plane under weight-bearing conditions. At the latest follow-up, 8 knees were rated as excellent, 38 knees as good, and 12 knees as fair, using our rating system. There was no loosening, osteolysis, or apparent polyethylene wear on plain radiographs. Varus-valgus instability of the knee was significantly reduced after total knee arthroplasty compared with the control value. However, tibiofemoral motion on the sagittal plane was significantly different from that of the normal knee, especially in the posterior cruciate sparing knees. Based on our results, we suggest that a long-term follow-up is necessary to establish whether the Osteonics total knee system truly reduces polyethylene wear.