Patent ID: 8192497

Claim:
A joint prosthesis comprising: a joint stem implantable into a bone and having a concavity therein; a conjoining member having a spheroidal body which, when disposed in the concavity, is free to swivel within the concavity in an unexpanded state but stationary within the concavity in an expanded state, the conjoining member having a bore formed in it which can receive an expander by means of which the conjoining member can be expanded to lock the conjoining member in a selected angular orientation; and a joint head having an articulation surface on one side thereof, the expander being tapered, wherein the bore in the conjoining member is inwardly tapered, and the joint head carries the expander on its underside opposite to the articulation surface, the expander being tapered inwardly towards its free end so that it can be received in the bore in the conjoining member so that, (i) the conjoining member is in the unexpanded state while the expander is not compacted relative to the conjoining member, allowing the joint head to be adjustably positionable in a plurality of medial-lateral and anterior-posterior orientations, and (ii) the conjoining member and the joint head can be fixed in a selected angular orientation by compacting the expander relative to the conjoining member to cause the conjoining member to expand.