Patent ID: 7615082

Claim:
An artificial ankle joint for replacement of an ankle joint in the body, said artificial ankle joint comprising: a first main articular surface which forms an articular socket for replacement of the tibia, said first main articular surface being composed of a concave curvature parallel to a main function plane of the joint corresponding to the sagittal plane, and a second main articular surface which cooperates mechanically with the first main articular surface as part of a condyle which replaces the talus and has convex curvatures in said main function plane coordinated with the first main articular surface; wherein the radii of the convex curvatures of the second main articular surface are smaller than the radii of the corresponding curvatures of the first main articular surface, thereby resulting in differential radii amounts, and wherein the resulting differential amounts of the corresponding radii of the first and second main articular surfaces deviate from one another in an upward-directed angular position (V) of the joint and in a downward-directed angular position (H); wherein the differential amounts of the radii between a medial side which is directed toward the center of the body and a lateral side which is directed laterally outwardly of the body differ from one another when the angular positions of the joint are the same, and wherein on the lateral side the radii of the curvature are smaller in the upward-directed angular position than in the downward-directed angular position, and on the medial side the radii of curvature are greater in the upward-directed angular position than in the downward-directed angular position.