A prosthesis (150) is disclosed. In one embodiment, the prosthesis has an external surface provided with two fixing means, each being configured for the exterior attachment of a modular peg (158)； and two conical modular pegs which extend in a direction normal to the external surface and which are configured such that each of their outer edges are parallel or converging, when in use. In another embodiment, the prosthesis has an external surface fitted with two conical permanent pegs which extend in a direction normal to the external surface and which are configured such that each of their outer edges are parallel or converging, when in use.
