Shoulder prosthesis

1. Stemless shoulder prosthesis comprising a fixation device for fixing the prosthesis to a resected humerus bone, the fixation device comprising

a base portion and

anchoring means, the base portion having a distal side adapted to contact a resection plane of the bone and a proximal side for carrying a humeral head, and the anchoring means being connected to the distal side of the base portion and adapted to fix the prosthesis to the bone,

wherein the anchoring means define a central axis perpendicular to the distal side of the base portion and a free central space around the central axis,

wherein the anchoring means comprise wall sections projecting from the base portion substantially perpendicular to the distal side of the base portion,

wherein each wall section includes a height, a length, and a width, and wherein the length is greater than the width and is measured between an inner and an outer edge of the wall section, wherein each wall section extends between the inner edge and the outer edge, and

wherein the wall sections have the height measured from the distal side of the base portion, the height of each wall section decreasing along its length from its outer edge towards the inner edge, each wall section having a maximum height at its outer edge and a minimum height at its inner edge, wherein the wall sections form a wall extending around the free central space, wherein the wall extends around the free central space in a closed loop; and

wherein the length of each wall section extends radially such that its outer edge meets the outer edge of a first adjacent wall section, and its inner edge meets the inner edge of a second adjacent wall section.

2. Stemless shoulder prosthesis according to claim 1 , wherein the wall sections are arranged around the free central space and are in particular evenly distributed.

3. Stemless shoulder prosthesis according to claim 1 ,

wherein the wall defines alternating radially outer convex wall portions and radially inner concave wall portions as the wall extends around the free central space.

4. Stemless shoulder prosthesis according to claim 1 , wherein the outer edge of each wall section is rounded.

5. Stemless shoulder prosthesis according to claim 1 , wherein each wall section is formed by two wall portions merging into one another at the outer edge of the wall section and each wall portion of a wall section merging into a wall portion of a neighboring wall section at a common transition zone.

6. Stemless shoulder prosthesis according to claim 5 , wherein the wall portions of each wall section extend at least partially parallel to each other.

7. Stemless shoulder prosthesis according to claim 5 , wherein each transition zone is rounded.

8. Stemless shoulder prosthesis according to claim 5 , wherein each wall section has a minimum height at the common transition zone.

9. Stemless shoulder prosthesis according to claim 1 , wherein each wall section comprises a distal edge which is formed at least partly as a cutting edge.

10. Stemless shoulder prosthesis according to claim 1 , wherein at least one of the wall sections and/or the base portion comprises at least one opening.

11. Stemless shoulder prosthesis according to claim 1 , wherein the base portion comprises a plate.