Modular humeral prosthesis for an inverted shoulder prosthesis
The invention relates to a modular humeral prosthesis for an inverse shoulder prosthesis, comprising an anatomical shaft ( 1 ) and a separable epiphyseal head ( 2 ) which may be angularly orientated by rotation about the longitudinal axis (XX) of the anatomical shaft. The anatomical shaft and the epiphyseal head comprise complementary angular indexing means ( 11, 28 ) for relative rotational fixation.
1. A modular humeral prosthesis comprising:
an anatomical stem having a longitudinal axis and including a hole;
a separable epiphyseal head which may be oriented angularly by rotation about the longitudinal axis of the anatomical stem and includes an axial hole;
a first contact surface on the epiphyseal head and a second contact surface on the anatomical stem, the first and second contact surfaces being in contact with each other;
the second contact surface being planar, perpendicular to the longitudinal axis and constituting a proximal extremity of the anatomical stem;
a screw which may pass through the axial hole provided in the epiphyseal head and into the hole in the anatomical stem to connect the epiphyseal head to the anatomical stem;
indicia of rotation between the epiphyseal head and the anatomical stem;
wherein the first contact surface extends laterally beyond the second contact surface of the anatomical stem whatever the angular orientation of the epiphyseal head with respect to the anatomical stem; and
wherein the epiphyseal head comprises a socket for receiving a cup of a reverse shoulder prosthesis cooperating with a scapular prosthesis.
2. The modular humeral prosthesis according to claim 1 and further comprising a plurality of notches provided on the first contact surface disposed according to a radial angular distribution about the longitudinal axis of the anatomical stem, and the anatomical stem includes a peg borne by the second contact surface and capable of cooperating with the notches.
3. The modular humeral prosthesis according to claim 1 , wherein the anatomical stem comprises at least one longitudinal rib for rotational locking.
4. The modular humeral prosthesis according to claim 1 , wherein a junction between the anatomical stem and the epiphyseal head is intended to be located inside a humerus when the prosthesis is in place, in order to take account of deltoid tension.
5. The modular humeral prosthesis according to claim 1 , wherein the indicia of rotation are provided in degrees of rotation.