Patent ID: 6235060
Filing Date: 2001-05-22
Classification: A61F

Abstract:
An artificial joint for use as an endoprosthesis for replacing a natural joint, said artificial joint comprising at least two artificial joint members each having curved articulation faces;wherein said joint is a flat or spherical four joint comprising first and second sides on opposite sides of a mid-plane;wherein on each side of the joint a curved contact boundary is formed on each of the articulation faces; the curved contact boundary on one of the articulation faces being part of an elliptical section contour of a first cylinder or cone representing a fixed joint member, and the curved contact boundary on the other of said articulation faces having the form of a counter track of a second cylinder or cone representing a moved joint member which rolls or slides on the first cylinder or cone;each side of said joint having a fixed or moving holoid lying in a reference plane or sphere, said reference plane or sphere being selected such that it lies between the condyles to be constructed;wherein a straight contact line along which the fixed and moved members touch at any given instant is drawn from a respective contact point lying on the curved contact boundaries eitherto a point which is fixed relative to the fixed or moved member and which lies in a randomly selected sagittal plane shifted toward the interior of the joint, orto the instantaneous center of revolution on the fixed or moving holoid; andwherein the sum of the straight contact lines forms a first contact face on the fixed member and a second contact face on the moved member, said first and second contact faces each representing a joint face of one of the two sides of the four-joint.