New jersey meniscal bearing knee replacement

Abstract

A prosthesis for the surgical replacement of a dysfunctional knee joint is disclosed. The prosthesis includes a tibial platform, one or two tibial bearing inserts, and a femoral component. In a unicompartmental embodiment of the invention, the tibial platform includes a spike for securing the tibial platform to the tibia. The tibial platform, in the unicompartmental embodiment, includes a track, which may be curved, and which is slidably engaged in dovetail fashion by a tibial bearing insert, typically of high molecular weight polyethylene. The superior surface of the tibial bearing insert is concave spherical, designed to slidably engage the inferior surface of the femoral component. The inferior surface of the femoral component is generally convex spherical, with radius of curvature slightly smaller than the radius of curvature of the tibial bearing insert. In some embodiments the inferior surface of the femoral component may have two or more differing radii of curvature at different points on such surface. Typically the tibial platform and the femoral component are constructed of cobalt-chromium alloy. In a bicompartmental or tricompartmental embodiment of the invention, the tibial platform includes two tracks, each of which may be curved, and each of which slidably engages in dovetail fashion a tibial bearing insert. The two tibial bearing inserts each engage, via their superior concave spherical surfaces, mating inferior convex surfaces of the femoral component. The two curved tracks are in general not concentric; rather, the center of each falls on a line normal to the plane of such curved track and passing through the center of curvature of the concave spherical surface of the tibial bearing insert of the other curved track.