Mobile-bearing Total Knee Prosthesis Research Articles

World Experience with Low Contact Stress Mobile-Bearing Total Knee Arthroplasty: A Literature Review

This article reviews recent data regarding the low contact stress (LCS) mobile-bearing total knee prosthesis recently published in the literature; conclusions are based on literature controls. The LCS Total Knee System (DePuy Orthopaedics Inc, Warsaw, Ind) has addressed the issues of implant polyethylene wear and implant-generated osteolysis. Patellar implant complications have been minimal despite the use of a mobile, metal-backed component. The original US Food and Drug Administration clinical investigation demonstrated favorable experience with cementless fixation. Results from numerous series indicate that the main problem with a mobile-bearing device is an early prosthetic failure resulting from bearing dislocation or breakage. Inadequate surgical technique will lead to femorotibial malalignment or ligamentous instability, which are factors that commonly result in revision. With the LCS Total Knee System, surgeons can use a tibia-cut-first approach with careful ligamentous balancing and flexion block spacing. The valgus lateral knee approach is an additional technique that has proved useful with this method.

Bilateral total knee arthroplasty: One mobile-bearing and one fixed-bearing.

We compared the early results of mobile-bearing knee prosthesis with fixed-bearing knee prosthesis in 16 patients who had one-stage, sequential, bilateral replacements. In each patient, a Low Contact Stress (LCS, Depuy) rotating-platform prosthesis was inserted in one side, and an Anatomic Modular Knee (AMK, Depuy) posterior-stabilised prosthesis was inserted in the other side. The same surgical routines were adopted for both sides in each patient. There were significant improvements in the Knee Society knee score and functional score, as well as the Oxford Knee score after both mobile-bearing and fixed-bearing knee replacements (p<0.001). However, we could not find any significant difference between the clinical results of the two prostheses. The authors early experience with the mobile-bearing total knee prosthesis was as favourable as the medium-term experience of the fixed-bearing total knee prosthesis in this prospective, match-pair study.

In Vivo Kinematic Analysis of a Mobile Bearing Total Knee Prosthesis

Ten normal subjects and 10 patients with a posterior cruciate retaining mobile bearing total knee replacement performed successive deep knee bends under fluoroscopy to determine tibiofemoral contact positions. At full extension the average initial contact position for the normal and mobile total knee replacement was 6.2 mm (range, 4.8 to 12 mm) anterior, and -4.4 mm (range, 3.9 to 11 mm) posterior to the sagittal tibial midplane, respectively. At 60 degrees flexion, the normal knee rolled back to -5.8 mm (range, -2.5 to -13.2 mm), whereas the mobile bearing total knee replacement rolled back to -9.2 mm (range, -4 to -17 mm). From 60 degrees to 90 degrees, normal knees rolled back to -7.8 mm (range, -5.8 to -13.8 mm), but the mobile bearing total knee replacement slid anteriorly to -5 mm (range, 2 to -12 mm). All mobile bearing total knee replacements had some form of roll back, but some slid anterior more than others. Five of 10 mobile bearing total knee replacements had some movement of the bearings while the others remained fixed. Patellar kinematics was similar to normal but reflected tibiofemoral abnormalities.