Polyethylene meniscal bearing of the Oxford knee produce conforming surfaces and are free to move with knee movements. We studied polyethylene wear of 23 meniscal bearings implanted after a mean time of 38 months. The mean penetration rate of the polyethylene was 0.026 mm per year, statistically correlated with implanted time. The large areas of contact provided by such design are able to reduce polyethylene wear in knee prosthesis at levels smaller to those reported for hip. We also studied bearing movement on six cadaveric specimens fixed in a six degrees of freedom rig. The movements take place in both compartments of the knee in the same direction as for normal menisci during flexion-extension and rotation. Unicompartmental arthroplasty using meniscal bearing knee can restore such movements when the anterior cruciate ligament is present.