Set of elements to be assembled in order to form a shoulder prosthesis

A set of elements to be assembled in order to form a shoulder prosthesis (1), comprising at least one humeral element (2) and at least one prosthetic head (3), the humeral element (2) comprising means for fastening to the humerus, in particular in the form of a slender rod (10) designed to be introduced into the medullary cavity of the humerus, and mounting means (3, 5, 6, 12, 23, 24, 25) for mounting the prosthetic head (3) according to a plurality of positions in relation to the humeral element, characterized in that

• said mounting means comprise a flat and circular proximal face (12) of the humeral element (2) and a projection (13) projecting from this face (12), coaxially thereto, this projection (13) being equipped with indexing means, with an inclined peripheral edge (15), at its free end, and with a groove (14) arranged in its periphery;
• the set of elements includes at least one intermediary element (5, 6), comprising a base (21, 31) and, on one side of this base (21, 31), a mounting end (22, 32);
• the base (21, 31) has a circular shape defined, on the side opposite the end (22, 32), by a flat face (23), and comprises a cavity (24, 34) arranged coaxially thereto, in which indexing means are formed which complement those comprised by said projection (13), this cavity (24, 34) being dimensioned in such a way as to receive said projection (13) in an adjusted manner;
• the base (21, 31) also comprises a groove arranged in the wall defining the periphery of said cavity (24, 34), receiving an elastically deformable split ring (25);
• this ring (25) is normally shaped such that it extends partially in the groove of the base (21, 31) and partially outside this groove, and can be elastically deformed in the direction of an increase of its diameter so as to be completely retracted in this groove;
• the mounting end (22, 32) is secured to said base (21, 31) and is arranged non-coaxially thereto, this end (22, 32) being configured to receive and retain the prosthetic head (3);
• the prosthetic head (3) comprises, at its axis, a cavity for receiving the mounting end (22, 32);
• the set is such that said intermediary element (5, 6) can be mounted on said humeral element (2) by engagement of said projection (13) in said cavity (24, 34), according to a plurality of angular positions around the axis of the projection (13) and of the cavity (24, 34) thanks to respective indexing means comprised by this projection (13) and this cavity (24, 34);
• during this engagement, said inclined peripheral edge (15) performs said elastic deformation of the ring (25), which allows the passage of this projection (13) beyond the ring (25);
• the arrival of the respective flat faces (12, 23) of the humeral element (2) and of the base (21, 31) in immediate proximity to each other coincides with the arrival of said groove (14) across from the ring (25);
• in this position, the latter resumes its normal shape through elastic return and as a result partially engages inside this groove (14), ensuring mounting of the intermediary element (5, 6) on the humeral element (2).