Ascension Orthopedics, Inc.

Steve Vander Meulen

Robert A Martin

Jerome J Klawitter

Jerome Klawitter

An orthopedic prosthetic implant comprises a metal alloy stem element (), which has one end portion () constructed to reside in the medullary cavity of a bone and an integral connector () at the opposite end to which crystalline brittle head (), preferably made of pyrocarbon-coated graphite, is joined. The head interfaces with human bone, and its effective joinder to the stem element is achieved through a polymeric insert () of proportional shape and design which has selected elastic properties. The design and material of the polymeric insert allow it to be securely received within an interior cavity () of the pyrocarbon-coated graphite head and mated to the stem connector in an either rigidly or bi-polar arrangement. The method of joinder allows the construction of composite implants that utilize the most desirable properties of metallic and brittle crystalline materials.

Prosthetic implant and assembly method

A prosthetic implant for partial resurfacing of the ulna at the distal radioulnar (DRU) joint which comprises a stem and an ulnar head. The combination of the anchoring stem and the head that is shaped and proportioned to replace only a portion of the distal ulnar head and the radial articulating surface and to interface with the resected ulna at a proximal stabilizing surface provides excellent stability in the completed implant. In the preferred embodiment, a pair of strategically located surfaces aligned at an obtuse angle provides the stabilizing surface arrangement. The provision of a set of such implants with different head and stem sizes allows a surgeon to best accommodate the physiology of a particular patient and locate a resurfaced head section offset from the canal center in order to provide a convex articular surface adjacent the radius which will allow the radius to smoothly pivot and translate around such resurfaced ulnar head during pivoting of the forearm.

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Leander, TX, United States of America

Steve Vander Meulen