Abstract: Joint prosthesis of perforated sheet metal strips which, for the formation of a hollow shaft, are welded together and to a collar having a protrusion for attaching to a ball joint. The collar is provided with an opening leading to the inside of the hollow shaft.

Abstract: Particles are sinter-fused onto the surface of a prosthesis shaft of titanium or titanium alloys. Before sinter-fusing, a coating material which forms below the .alpha.-.beta.-transition temperature a liquid phase with the material of the prosthesis and particles is applied to provide a coating between the shaft and particles.

Abstract: Method for implanting and subsequently removing mechanical implants of an Ni-Ti or a Ti-Nb alloy material which exhibits the memory effect which occurs due to heating of the implant to a temperature above the specific temperature for the alloy material. The memory effect is actuated by heating the implant after implantation of same in the living tissue, and upon completion of the healing process, the implant is substantially returned to its shape upon implantation by cooling it to a temperature below the temperature which actuates the opposite memory effect to facilitate removal.