Mobile Bearing Knees
Mobile bearing knees were designed to reduce the wear of the polyethylene tibial bearing in total knee replacement. As with fixed bearing knees, they have been around for over 30 years with very good clinical results. The difference between a mobile bearing and a fixed bearing device is that in the fixed bearing, the polyethylene is rigidly fixed to the tibia and all prosthetic motion occurs between the femoral implant and the polyethylene bearing.
The Mobile bearing, on the other hand, has a polyethylene bearing that can rotate on a metal base plate, which is attached to the tibia. The motion in this type of knee occurs between the femoral implant and the tibial bearing, and between the bearing and the tibial baseplate. In lab studies, this has been shown to reduce the amount of wear of polyethylene relative to a fixed bearing device. I have used mobile bearing knees since 1993 with excellent clinical results and continue to use this technology in many patients.