Other

Depuy Products, Inc.

Robert Beckenbaugh

Robert J Ball

William B Geissler

Ian A Trail

Dave Cox

Raphael Pascaud

Ted Bolinger

A distal component for a wrist prosthesis that utilizes fixation within the carpus complex, incorporates features that improve the probability of intercarpal fusion and allows modularity of articulating components. In one form, the subject invention includes an ovoid fixation plate having three holes and a boss. The three holes allow attachment of stems and/or screws distally for fixation in the carpus. The boss projects proximally from the plate, and serves as an attachment point for the articulating head. Modularity of the fixation and articulating components allow a surgeon many options for optimizing fixation distally, and articulation proximally. The proximal head of the distal component is designed to articulate with existing radial components. Since the proximal head of the distal component is modular, however, the head can be redesigned to accommodate later design changes in proximal components.

Distal component for wrist prosthesis

A total wrist prosthesis which has a metacarpal component and a radial component having ellipsoidal articulating surfaces. The metacarpal component and the radial component each have a fixation stem for insertion into the third metacarpal and the radius respectively. The fixation stem of the metacarpal component is curved dorsally to volarly so as to approximate the natural curvature of the third metacarpal and capitate of the human hand. The fixation stem of the metacarpal component has a center line which attaches to the head of the metacarpal component which contains the articulating surface dorsally from the minor axis of the ellipsoidal articulating surface. The fixation stem and the head of the metacarpal component have a plurality of wings attached thereto and a spur to prevent rotation of the device once inserted into the metacarpal. Also, the surface area of the metacarpal component proximal to the ellipsoidal articulating surface is coated with porous coating to aid in cement fixation. The radial component of the wrist prosthesis also has a fixation stem which is fixedly attached to a holder which receives a bearing member that defines a concave ellipsoidal articulating surface which is complimentary to the convex articulating surface of the metacarpal component. The center line of the fixation stem of the radial component is displaced dorsally from the minor axis of the concave articulating surface and also radially from the minor axis. A porous coating is also present about the base of the holder and the fixation stem. The curvature of the metacarpal fixation stem and the displacement of the center lines of both fixation stems relative to the minor axis of the ellipsoidal surfaces to which they are attached cause the center of rotation and flexion-extension motion and radial-ulnar-deviation to approximate the natural centers of rotation of flexion-extension motion and radial-ulnar-deviation.

Total wrist prosthesis

Growing community of inventors

Rochester, MN, United States of America

Robert Beckenbaugh