Humeral component of a shoulder joint prosthesis

1. A reverse shoulder joint prosthesis for implantation at least partially within an intramedullary cavity of a humerus bone, comprising:

a stem part having an elongated portion configured for location within the intramedullary cavity, a stem connection feature having a connection axis, and a stem axis defined as extending centrally through the elongated portion;

an epiphyseal part connected to the stem part and having a bone engaging surface, a concave bearing surface defining an epiphyseal axis and a epiphyseal connection feature configured to mate with the stem connection feature; and

wherein the epiphyseal axis is offset posteriorly relative to the stem axis and the connection axis is parallel with the stem axis when the stem part is assembled with the epiphyseal part and wherein, when in use, the bone engaging surface of the epiphyseal part and at least a portion of the stem part are adapted to contact at least an aspect of the humerus bone.

2. The reverse shoulder joint prosthesis of claim 1 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of at least about 1.5 mm.

3. The reverse shoulder joint prosthesis of claim 1 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of not more than about 7 mm.

4. The reverse shoulder joint prosthesis of claim 1 , wherein the connection axis is coincident with the stem axis when the stem part is assembled with the epiphyseal part.

5. The reverse shoulder joint prosthesis of claim 4 , wherein one of the stem connection feature and the epiphyseal connection feature is a socket and the other of the stem connection feature and the epiphyseal connection feature is a spigot configured to be received in the socket.

6. The reverse shoulder joint prosthesis of claim 4 , wherein the connection feature on the epiphyseal part is offset relative to the epiphyseal axis.

7. The reverse shoulder joint prosthesis of claim 1 , wherein the epiphyseal part comprises a shell part that defines a recess, and a bearing part configured to be received in the shell part, the bearing part including the concave bearing surface for articulation with a glenoid component.

8. The reverse shoulder joint prosthesis of claim 7 , wherein a rim of the shell part is approximately circular.

9. The reverse shoulder joint prosthesis of claim 8 , wherein the rim of the shell part is approximately planar.

10. The reverse shoulder joint prosthesis of claim 9 , wherein the plane defined by the rim of the shell part is approximately perpendicular to the epiphyseal axis.

11. The reverse shoulder joint prosthesis of claim 1 , wherein an angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is at least about 20°.

12. The reverse shoulder joint prosthesis of claim 11 , wherein the angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is not more than about 35°.

13. The reverse shoulder joint prosthesis of claim 1 , further comprising

a glenoid component that includes a convex head part configured to be received in the epiphyseal part and articulate with the concave bearing surface.

14. The reverse shoulder joint prosthesis of claim 1 , wherein the stem part and the epiphyseal part are rotatable with respect to one another about the stem axis from a first position to a second position that is angularly offset from the first position.

15. A reverse shoulder joint prosthesis for implantation at least partially within an intramedullary cavity of a humerus bone, comprising:

a stem part having an elongated portion configured for location within the intramedullary cavity, a stem connection feature having a connection axis, and a stem axis defined as extending centrally through the elongated portion;

an epiphyseal part connected to the stem part and having a bone engaging surface, a concave bearing surface defining an epiphyseal axis; and

wherein the stem part and the epiphyseal part are rotatable with respect to one another about the stem axis from a first position to a second position that is angularly offset from the first position, wherein an angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is the same when the stem part and the epiphyseal part are in the first position and the second position, wherein the epiphyseal axis is offset posteriorly relative to the stem axis and the connection axis is parallel with the stem axis when the stem part is assembled with the epiphyseal part, and wherein, when in use, the bone engaging surface of the epiphyseal part and at least a portion of the stem part are adapted to contact at least an aspect of the humerus bone.

16. The reverse shoulder joint prosthesis of claim 15 , wherein the angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is at least about 20°.

17. The reverse shoulder joint prosthesis of claim 15 , wherein the angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is not more than about 35°.

18. The reverse shoulder joint prosthesis of claim 15 , further comprising a glenoid component that includes a convex head part configured to be received in the epiphyseal part and articulate with the concave bearing surface.

19. The reverse shoulder joint prosthesis of claim 15 , wherein the connection axis is coincident with the stem axis when the stem part is assembled with the epiphyseal part.

20. The reverse shoulder joint prosthesis of claim 19 , wherein the epiphyseal part includes an epiphyseal connection feature configured to mate with the stem connection feature, and wherein one of the stem connection feature and the epiphyseal connection feature is a socket and the other of the stem connection feature and the epiphyseal connection feature is a spigot configured to be received in the socket.

21. The reverse shoulder joint prosthesis of claim 19 , wherein the connection feature on the epiphyseal part is offset relative to the epiphyseal axis.

22. The reverse shoulder joint prosthesis of claim 19 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of not more than about 7 mm.

23. The reverse shoulder joint prosthesis of claim 15 , wherein the epiphyseal part comprises a shell part that defines a recess, and a bearing part configured to be received in the shell part, the bearing part including the concave bearing surface for articulation with a glenoid component.

24. The reverse shoulder joint prosthesis of claim 23 , wherein a rim of the shell part is approximately circular.

25. The reverse shoulder joint prosthesis of claim 24 , wherein the rim of the shell part is approximately planar.

26. The reverse shoulder joint prosthesis of claim 25 , wherein the plane defined by the rim of the shell part is approximately perpendicular to the epiphyseal axis.

27. The reverse shoulder joint prosthesis of claim 15 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of at least about 1.5 mm.

28. A reverse shoulder joint prosthesis for implantation at least partially within an intramedullary cavity of a humerus bone, comprising:

a stem part having an elongated portion configured for location within the intramedullary cavity, a stem connection feature having a connection axis, a stem axis defined as extending centrally through the elongated portion, and a proximal face having an aspect that is planar and perpendicular to the stem axis;

an epiphyseal part connected to the stem part and having a bone engaging surface, a distal face having an aspect that is planar, a concave bearing surface defining an epiphyseal axis, and an epiphyseal connection feature configured to mate with the stem connection feature; and

wherein, when the stem part is assembled with the epiphyseal part, the proximal face of the stem contacts the distal face of the epiphysis, the epiphyseal axis is offset posteriorly relative to the stem axis, and the connection axis is coincident with the stem axis, and wherein, when in use, the bone engaging surface of the epiphyseal part and at least a portion of the stem part are adapted to contact at least an aspect of the humerus bone.

29. The reverse shoulder joint prosthesis of claim 28 , wherein the stem part and the epiphyseal part are rotatable with respect to one another about the stem axis from a first position to a second position that is angularly offset from the first position, and wherein the angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is the same when the stem part and the epiphyseal part are in the first position and the second position.

30. The reverse shoulder joint prosthesis of claim 28 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of at least about 1.5 mm.

31. The reverse shoulder joint prosthesis of claim 28 , wherein the stem axis and the epiphyseal axis define a distance separating one from the other of not more than about 7 mm.

32. The reverse shoulder joint prosthesis of claim 28 , wherein one of the stem connection feature and the epiphyseal connection feature is a socket and the other of the stem connection feature and the epiphyseal connection feature is a spigot configured to be received in the socket.

33. The reverse shoulder joint prosthesis of claim 28 , wherein the connection feature on the epiphyseal part is offset relative to the epiphyseal axis.

34. The reverse shoulder joint prosthesis of claim 28 , wherein the epiphyseal part comprises a shell part that defines a recess, and a bearing part configured to be received in the shell part, the bearing part including the concave bearing surface for articulation with a glenoid component.

35. The reverse shoulder joint prosthesis of claim 34 , wherein a rim of the shell part is approximately circular.

36. The reverse shoulder joint prosthesis of claim 35 , wherein the rim of the shell part is approximately planar.

37. The reverse shoulder joint prosthesis of claim 36 , wherein the plane defined by the rim of the shell part is approximately perpendicular to the epiphyseal axis.

38. The reverse shoulder joint prosthesis of claim 34 , further comprising a glenoid component that includes a convex head part configured to be received in the epiphyseal part and articulate with the concave bearing surface.

39. The reverse shoulder joint prosthesis of claim 28 , wherein an angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is at least about 20°.

40. The reverse shoulder joint prosthesis of claim 28 , wherein the angle defined by the stem axis and the epiphyseal axis, when viewed along the anterior-posterior axis, is not more than about 35°.