Abstract: A prosthesis for the distal radioulnar joint of a patient includes an elongated rod which is formed with a pin at one end, and which has a body portion that can be attached to the ulna of the patient. Also included is a ball which is formed with a channel for receiving the pin of the rod therein to establish a relative translational motion between the ball and the rod. The prosthesis further includes a brace which has both a cover plate and a base plate. The base plate has a seat which is specifically shaped to support the ball and the base plate is formed with an extension which can be affixed to the radius of the patient. With the base plate mounted on the radius, the cover plate of the brace is secured to the base plate with the ball held between the two plates to establish a relative rotational motion between the ball and the brace. With this overall structure, a relative general motion is established between the rod (ulna) and the brace (radius).