Abstract: A finger prosthesis includes a first screw to be received in an intramedullary canal of a phalange. The first screw includes a first head defining a first longitudinal bore therein. There is provided a second screw to be received in an intramedullary canal of another, adjoining phalange. The second screw includes a second head defining a second longitudinal bore therein. The prosthesis further has a first joint part having a convex semi-cylindrical surface, a transverse slot and a bore hole, a pivot pin held in the bore hole and traversing the transverse slot. The first piston is secured to the pivot pin for swinging motion in the transverse slot. The first piston is received in the first longitudinal bore for sliding motions therein. There is further provided a second joint part situated between the first head and the first joint part and having a concave semi-cylindrical surface slidingly contacting the convex semi-cylindrical surface of the first joint part.

Abstract: A thumb prosthesis includes a trapezial component adapted to be fixed in the trapezium and a metacarpal component adapted to be fixed in the metacarpal bone. The trapezial component has a self-cutting thread adapted to be screwed into the trapezium; a polygonal base, having a conical surface and a neck part and being situated at one end of the self-cutting thread; and a spherical head disposed on the conical surface and extending from the neck part. The metacarpal component has a frustoconical head having a large-diameter end and an opposite, small-diameter end and a geometrical axis; a hemispherical socket provided in the small-diameter end and receiving a surface portion of the spherical head; and a stem extending from the large-diameter end of the frustoconical head. The stem is offset relative to the geometrical axis and has a decreasing triangular cross section with rounded corners as viewed in a direction away from the frustoconical head.