Orthopaedic implant for arthroplasty of the fingers

摘要

An orthopaedic implant used in arthroplasty of the fingers comprises a first element for a proximal phalanx and a second element for an adjacent distal phalanx, each element having a respective stem for implantation in the bone and an interphalangeal articulation head, the head of the first element having a biconvex surface of articulation, with a central valley, and the head of the second element having a biconcave surface of articulation designed to cooperate with said convex surface and comprising a central crest. At rest, the surfaces are congruent in the frontal plane of the articulation in the area of the condyles and non-congruent in the sagittal plane.

主权项

1. An orthopedic implant used in arthroplasty of the fingers, comprising a first element for implantation in a proximal phalanx and a second element for implantation in an adjacent distal phalanx, each element having a respective stem sized for implantation in the respective phalanx and an interphalangeal pivot head, a head of the first element having a biconvex condylar pivot surface including a central valley having a radius of curvature R5 in the frontal plane, and a head of the second element having a biconcave condylar pivot surface designed to fit generally complementarily with the biconvex condylar pivot surface including a central ridge having a radius of curvature R6 in the frontal plane,
wherein the biconcave and biconvex condylar pivot surfaces at rest are congruent in the frontal plane and are not congruent in the sagittal plane, and wherein radii of curvature R1, R′1 of the biconvex condylar pivot surface of the first element are identical to respective radii of curvature R2, R′2 of the biconcave condylar pivot surface of the second element in the frontal plane, and wherein the central valley of the biconvex condylar pivot surface and the central ridge of the biconcave condylar pivot surface define an intercondylar space along a length of the central valley, the intercondylar space having a volume between 15 mm3 and 30 mm3.