Joint arthroplasty device and method

1. An implant comprising:

a joint facing surface and a bone facing surface forming a body member therebetween;

an axial end of a central post directly connected to, and extending out from, a first portion of the bone facing surface and configured to be received in a bone recess in a bone created during a preparation of the bone;

a ring member extending out from a second portion of the bone facing surface spaced from the first portion to a free end disposed for insertion into a second bone recess of the bone created during the preparation of the bone, said ring member having a radial outermost surface spaced radially inwardly from a radial outermost surface of said body and a radial innermost surface radially spaced from said central post;

a dorsal member extending from a dorsal end of the body member; and

wherein the dorsal member extends radially and axially from a circumferentialmost portion of the body member, wherein the dorsal member comprises an inner surface and an outer surface.

2. The implant of claim 1 , wherein the dorsal member comprises a convex exterior surface and a concave bone facing surface.

3. The implant of claim 2 , wherein the ring member comprises a barb for promoting fixation of the bone.

4. The implant of claim 3 , wherein the ring member is inset from the perimeter of the body member and the bone facing surface comprises an inset region between the perimeter of the body member and the ring member.

5. The implant of claim 4 , wherein the inset region is concave.

6. The implant of claim 1 , wherein the post is centered on the bone facing surface of the body member.

7. The implant of claim 6 , wherein the ring member is concentric with the post.

8. The implant of claim 7 , wherein the post is barbed.

9. The implant of claim 1 , wherein the ring member is centered on the body member.

10. The implant of claim 9 , wherein the ring member comprises a barb.

11. The implant of claim 10 , wherein the dorsal member further comprises a hole extending from the outer surface to the inner surface.

12. The implant of claim 1 further comprising a screw plug for retaining said post.

13. The implant of claim 1 wherein said post extends axially away from said bone facing surface further than said free end of said ring member.

14. The implant of claim 1 wherein said radial innermost surface, said central post and said bone facing surface bound a cavity for receiving a screw plug.

15. An implant comprising:

a joint facing surface and a bone facing surface forming a body member therebetween;

an axial end of a central post directly connected to, and extending out from, a first portion of the bone facing surface and configured to be received in a bone recess in a bone created during a preparation of the bone;

a ring member extending out from a second portion of the bone facing surface spaced from the first portion to a free end disposed for insertion into a second bone recess of the bone created during the preparation of the bone, said ring member having a radial outermost surface spaced radially inwardly from a radial outermost surface of said body and a radial innermost surface radially spaced from said central post;

a dorsal member extending from a dorsal end of the body member;

and

a screw plug for retaining said post.

16. An implant comprising:

a joint facing surface and a bone facing surface forming a body member therebetween;

an axial end of a central post directly connected to, and extending out from, a first portion of the bone facing surface and configured to be received in a bone recess in a bone created during a preparation of the bone;

a ring member extending out from a second portion of the bone facing surface spaced from the first portion to a free end disposed for insertion into a second bone recess of the bone created during the preparation of the bone, said ring member having a radial outermost surface spaced radially inwardly from a radial outermost surface of said body and a radial innermost surface radially spaced from said central post;

a dorsal member extending from a dorsal end of the body member; and

wherein said radial innermost surface, said central post and said bone facing surface bound a cavity for receiving a screw plug.