Mayo Foundation for Medical Education and Research

Orthomet, Inc.

Ronald L Linscheid

William P Cooney, Iii

Albert L Lippincott, Iii

David A Leibel

Richard A Berger

An anatomical prosthesis for implantation after a resection of the distal ulna includes a head and a stem. The head is formed with a curved surface for articulation with the sigmoid notch of the distal radius. A bore is provided in the head to allow for attachment of the head to the stem. The head is further formed with suture holes for anchoring the head to the soft tissues such as the ulnar collateral capsule, the triangular fibrocartilage and the extensor carpi ulnaris subsheath that are exposed after resection of the distal ulna. The stem is elongated, having a proximal end for engagement with the intramedullary canal of the ulna, and a distal end for engagement with the bore formed in the head.

Ulnar implant system

A joint prosthesis is provided for replacing a joint between two bones in which one bone is normally permitted a substantial degree of rotary circumduction with respect to a second bone. A first member of the prosthesis is provided with a coupling portion enabling it to be attached to the elongated bone and includes a head having a generally saddle-shaped articulating surface facing away from the stem. The second member similarly has a connector adapted to connect the second member to the second bone, and has a head provided with a saddle-shaped articulating surface configured and sized to articulate with the saddle-shaped surface of the first member to enable one of the long bones to move in rotary circumduction with respect to the other. The saddle-shaped surfaces preferably are substantially congruent in shape.

Joint prosthesis enabling rotary circumduction

A joint prosthesis for replacing a joint between two elongated bones of the hand. A first member is provided with an elongated stem for reception in one of the elongated bones and includes a head remote from the stem, the head having a convex articulating surface and lateral articulating surfaces adjacent the convex surface and on each side thereof. A second member has a stem for reception in the other bone and a base remote from the stem, the base having a concave articulating surface and lateral articulating surfaces on each side thereof, the concave and lateral surfaces being adapted to engage and articulate with the respective convex and lateral articulating surfaces of the first member. The lateral articulating surfaces of the first and second members being positioned to fully engage and articulate with each other to thereby restrain lateral articulation only when the bones are articulated through at least 30 degrees of flexion, and at 90 degrees of flexion, the force between said members is borne primarily by said lateral articulating surfaces.

Growing community of inventors

Rochester, MN, United States of America

Ronald L Linscheid