Shaft component for a joint endoprosthesis

A shank unit for an endo joint prosthesis to be implanted in a tubular bone and comprising

• a hollow, cylindrical anchoring sub-assembly (2) having a longitudinal axis (1) and being substantially rotationally symmetrical,
• said anchoring sub-assembly comprising a plurality of coaxial, hollow cylindrical segments enlarging toward an upper end of said sub-assembly, said segments having perforated outer surfaces;
• an articulating sub-assembly (3) detachably connectable to said upper end of said anchoring sub-assembly (2), said articulating sub-assembly including
• a substantially rotationally symmetrical base element (31),
• an axis of rotation (32), and
• a neck extension (33) mounted eccentrically on said base element and subtending an angle of less than 90.degree. with said axis of rotation (32) for receiving a joint ball (36);
• said base element of said articulating sub-assembly being detachably mountable on said on said anchoring sub-assembly (2) with the axes of said anchoring and articulated sub-assemblies coincident and with said articulated subassembly in any selected rotational angular position relative to said anchoring subassembly such that a radial position of said neck extension can be selected to adjust anterior torsion to a desired level.