Abstract: A prosthetic joint for replacing a finger joint, including a shell-like member which is secured to the distal end of one phalanx, this shell-like joint having a vertical cross section which resembles a semicylindrical shell. The shell preferably has parallel legs extending rearwardly from the edges of the semicylindrical portion, with the lowermost leg having a greater rearward extension. The shell has a transverse cross section which results in two convex bearing surfaces symmetrically positioned relative to the central vertical plane of the shell. These convex bearing surfaces define a groove therebetween at the central vertical plane. The other joint member includes a tack portion which extends into the other phalanx, which tack portion has an enlarged head provided with a concave bearing surface for engagement with the exterior bearing surface on the shell.

Abstract: An implantable joint for replacing a human toe joint. The joint includes a one-piece tack member implantable into the distal end of a metatarsal, and a one-piece socket member implantable into the proximal end of a phalanx. The tack member has an enlarged head defining a smooth part-spherical convex bearing surface which engages a smooth part-spherical concave bearing surface on an enlarged head of the socket member. The head of the socket member is elliptical in cross section so that the concave bearing surface extends through about 90.degree. in the vertical direction. The convex bearing surface of the tack member is nonsymmetrical relative to the longitudinal axis and extends through an angle which closely approximates 180.degree., with this bearing surface projecting downwardly from the horizontal longitudinal axis through an extent greater than 90.degree..

Abstract: An endoprosthetic joint used to replace a dysfunctional thumb carpometacarpal joint comprises a first, or metacarpal, component adapted for insertion into the first metacarpal of the thumb and carrying thereon the ball portion of a ball-and-socket joint. In one embodiment, said joint further comprises a second or base portion of slightly flexible material defining a socket into which said ball is snappably received and having a projection thereon for reception into a suitably prepared recess in the trapezium bone of the hand. Both said components are cemented into place for firm holding therein. In a second embodiment, the metacarpal portion is identical with, and the base portion is generally similar to, that of the first embodiment.

Abstract: Prosthetic knee joint. A prosthetic knee joint is proposed which incorporates into a single product a variety of previously recognized desirable features. The joint in question has a generally cylindrically shaped knob on one component thereof and a receptacle for receiving said knob in the other component thereof. Said receptacle is designed for full engagement of said cylindrical knob less only the clearance required to permit the desired pivotal motion of said joint and the components defining said receptacle are arranged so that only shear stress is normally imposed on the screws by which the components defining said receptacle are assembled and the parts are further arranged in order that wide contact surfaces between the components of said prosthesis are provided for direct transmission of load between said components without a major portion thereof being transmitted through said joint.

Abstract: Tool for inserting a component of a prosthetic implant, primarily a component of a finger knuckle joint, said component having a joint portion and a prong portion. There is provided a tool having at one end thereof a suitable receptacle for receiving said joint portion and holding same firmly for inserting the prong portion of said implant as desired into a bone and then easily detaching said tool from the prosthesis. In the disclosed embodiment, the prosthesis has in its joint portion a somewhat cylindrical bearing part and the tool for handling same is provided with a generally cylindrical receptacle for receiving same with, however, one portion thereof cut out for the easy removal of the tool from said prosthesis.

Abstract: An endoprosthetic joint formed by head and socket members which are adapted to be implanted in a thumb or a finger and can be suitably snapped together. The socket member is provided with structure exteriorly thereof, such as a pair of outwardly projecting webs disposed on diametrically opposite sides thereof, for permitting the muscles, ligaments and tendons to be sutured to these webs to thereby positionally relate same to the implanted joint, whereby proper balancing in the tensions imposed on the muscles and tendons is achieved during pivoting of the digit.

Abstract: Wrist joint prosthesis. As a replacement for the joint in a human wrist, there is provided a prosthesis permitting both vertical motion, sidewise motion and rotary motion but preventing twisting motion around an axis projecting from and parallel with the lower forearm. For this purpose, there is provided a metal socket fitted with a prong receivable into a bone of the forearm. A plastic cup made of material self-lubricating with respect to such metal socket is fitted within said socket, snappable thereinto to resist but not prevent withdrawal therefrom and having a rectangular projection-and-slot relationship with said metal socket to permit relative motion with respect thereto in only a single plane.

Abstract: Endoprosthetic joint particularly one permitting no appreciable adduction or abduction. There is provided an endoprosthesis for ginglymus joints comprising a first part made from a metal inert to the human body and having a substantially cylindrical head. A second part is provided of molded plastics material having a socket of substantially cylindrical shape for receiving said head. A ridge is provided around the entire perimeter of the aperture through which access to said socket is obtained, which ridge is of dimension to permit the parts to be snapped together manually but to provide substantial resistance against their becoming unsnapped. Further, the cylindrical head is only a clearance distance shorter than the corresponding dimension of the socket whereby swing motion of said head within said socket is substantially prevented.