Patent ID: 6344059
Filing Date: 2002-02-05
Classification: A61F

Abstract:
A replacement knee prosthesis comprising a femoral component (1) for attachment to the femur of a user and a plastic tibial component placed in a metal tray (3) which can be fixed to the tibia of the user, the femoral component (1) having a lateral surface generated by a logarithmic spiral generatrix (4) and a medial surface generated by a conical spiral generatrix (5), said tibial component (2) having a camber (10) of trough-like shape in which a lateral surface (8) of the trough-like shape camber corresponds to a rolling-down of said logarithmic spiral generatrix (4) of the femoral component (1) and a medial surface (9) of the trough-like shape camber corresponds to the rolling-down of said conical spiral generatric (5) of the femoral component (1), wherein said lateral surface of the femoral component is defined by a two parameter equation as follows:x=([cek&PHgr;âˆ’R]+R cos &thgr;) cos &PHgr;y=([cek&PHgr;âˆ’R]+R cos &thgr;) sin &PHgr;z=Â±R sin &thgr;where &thgr; is the central angle of the circle arc segment with R=35 mmsaid medial surface of the femoral component being defined by the two parameter equation as follows: x=([aek&PHgr;âˆ’R]+R cos &thgr;) cos &PHgr;y=([aek&PHgr;âˆ’R]+R cos &thgr;) sin &PHgr;z=aek&PHgr;Â±R sin &thgr;where &thgr; is the central angle of the circle arc segment with R=35 mm.