Patent ID: 6699291
Filing Date: 2004-03-02
Classification: A61F

Abstract:
A knee prosthesis comprising:a U-shaped femur prosthetic element defining a housing for engaging the resectioned epiphysial portion of a femur and comprising an anterior portion defining a trochlea on its front face and a distalo-posterior portion defining two condyles between which said portion forms a block presenting, in its outer face relative to the housing, a lug connected to the trochlea and adjacent to a notch from which a convex bearing surface extends to the rearmost portion of the block; and a tibia prosthetic element comprising a base for fitting to the resectioned epiphysial portion of a tibia, and an insert mounted on the base and presenting, facing the femur prosthetic element, two glenoid cavities for co-operating with the condyles, said element including between the glenoid cavities an elevation of sagittal orientation co-operating with the front edge of said insert to define a projection for antero-posterior stabilization which is engaged in the notch in the extended position of the prosthesis and which is connected to a concave sliding ramp extending to the rear edge of the insert and co-operating with the convex portion facing it in the extended position of the prosthesis to define a gap of section that increases from the zone where the projection and the notch are in contact all the way to said rear edge, wherein the convex bearing surface is defined by: a transverse radius of curvature Rt of center O occupying an angular extent at; and a sagittal curve made up of: Ã  a substantially middle portion of radius R35, of center O, and occupying an angular extent a35; Ã  a front portion connecting the middle portion to the notch, having a radius R34, a center O1 situated beyond and beneath the center O relative to the anterior portion of the prosthetic element, and occupying an angular extent a34; and Ã  a rear portion having a radius R36, a center O2 situated beyond and beneath the center O relative to said anterior edge, and occupying an angular extent a36.