Method and apparatus for wrist arthroplasty

Abstract

A radiocarpal wrist joint replacement includes a radial member configured to be affixed to a portion of an end of the radial bone proximal to the wrist including a fixture to be affixed over a longitudinal aspect of the radial bone and a radial resurfacing plate having a substantially concave surface configured to be located at the end of the radial bone. A carpal capitate bone insert configured to be inserted and affixed into the carpal capitate bone. A bulbous component includes a first convex head and a second convex head, substantially opposite each other and connected by a neck defining an annular groove between the first convex head and the second convex head. The carpal capitate bone insert is configured to be flexibly coupled to the first convex head of the bulbous component. The radial resurfacing plate of the radial member with the concave surface is configured to be operably coupled to the second convex head of the bulbous component so as to allow radial freedom of motion in the joint replacement.

1 . A distal radioulnar joint replacement apparatus for implantation in a wrist of a subject, the apparatus comprising:
 a sigmoidal member configured to be affixed onto a portion of an end of the radial bone proximal to the wrist including a lower mounting bracket to be affixed over a longitudinal aspect of the radial bone so as to face the ulna bone, the sigmoidal member including a hook; and   an ulnar member configured to be affixed to a portion of an end of the ulna bone proximal to the wrist and opposite to the sigmoidal member, the ulnar member including a bore configured to receive hook, and retain the hook after implantation,   wherein the bore is shaped so as to allow relative movement between the radial bone and the ulna bone so as to facilitate supination and pronation movement of the wrist of the subject.   
     
     
         2 . The apparatus of  claim 1 , wherein the sigmoidal member comprises a triangular peg implanted into cancellous bone at the end of the radius bone. 
     
     
         3 . The apparatus of  claim 2 , wherein the triangular peg comprises a threaded hole for receiving a screw. 
     
     
         4 . The apparatus of  claim 3 , wherein the sigmoidal member comprises a screw hole configured to enable threading of a screw through the screw hole and the radius bone and into the threaded hole. 
     
     
         5 . The apparatus of  claim 1 , wherein the bore is C-shaped. 
     
     
         6 . The apparatus of  claim 1 , wherein the ulnar member is formed from a receptacle piece and a mounting piece. 
     
     
         7 . The apparatus according to  claim 6 , wherein the receptacle piece is formed from mobile polyethylene or pyrocarbon. 
     
     
         8 . The apparatus according to  claim 6 , wherein the mounting piece is formed from stainless steel or titanium. 
     
     
         9 . The apparatus of  claim 6 , wherein the receptacle piece includes the bore. 
     
     
         10 . The apparatus of  claim 6 , wherein the receptacle piece includes rails and the mounting piece includes tracks configured to receive the rails to hold the receptacle piece on the mounting piece. 
     
     
         11 . The apparatus of  claim 6 , wherein the mounting piece includes a plurality of screw holes configured to endable affixing the mounting piece to the ulna bone. 
     
     
         12 . The apparatus of  claim 1 , wherein the lower mounting bracket includes at least one screw hole configured to enable affixing the lower mounting bracket to an ulnar side of the radius bone. 
     
     
         13 . The apparatus of  claim 12 , wherein said at least one screw hole comprises two screw holes. 
     
     
         14 . The apparatus of  claim 1 , wherein the ulnar member comprises a plurality of screw holes to enable affixing the ulnar member to the ulnar bone. 
     
     
         15 . The apparatus of  claim 14 , wherein a screw hole said plurality of screw holes is configured to enable threading of a screw through that screw hole through an ulnar head into a hole in a triangular block of the ulnar member. 
     
     
         16 . the apparatus of  claim 14 , wherein a screw hole said plurality of screw holes has an oval shape.