A total prosthesis for the wrist is indicated in case of painful, functionally impairing joint damage as a result of rheumatoid arthritis or degenerative arthrosis. In contrast to wrist fusion, total wrist arthroplasty is a motion preserving operation designed to prolong wrist function over time.
The MWP III Total Wrist Prosthesis, designed for uncemented anchoring, is a direct further development of the cemented wrist prosthesis MWP I, implanted for the first time in 1971 and has been constantly improved, last time 2003. The prosthesis is designed as a ball-and-socket joint. The carpal component consist of a socket-shaped part plus the anchoring stems, which are tilted in a dorsal direction in respect of the joint socket and offset in a radial direction. The ulnar stem runs parallel to the radial stem and leads into the socket part at an angle. The radial component consists of the U-shaped anchoring stems and a built-in ball part. The ball is offset towards the ulna, and the base of the ball corresponds to the joint between the radius and the lunate bone.