System, including apparatus, methods, and kits, for replacement of the proximal end of a radial bone with a prosthesis having a floating articular member. The prosthesis may include a head portion connected or connectable to a stem portion. While the stem portion remains operatively connected to the head portion, the head portion and/or an articular member thereof may be permitted to float in position relative to the stem portion. The head portion/articular member may float transversely (e.g., translationally) and/or rotationally with respect to the stem portion. The articular member may articulate with a humeral bone or both a humeral bone and an ulnar bone. In some embodiments, the head portion may include a fixed member for articulation with an ulnar bone and a floating member for articulation with a humeral bone.

System, including methods and apparatus, for replacing an end of a bone, such as a radial bone, with a prosthesis. In exemplary embodiments, the prosthesis is a radial head prosthesis having a stem portion and a head portion. The head portion may be configured to be (a) placed onto the stem portion by movement of the head and stem portions relative to one another transverse to a longitudinal axis of the stem portion, and then (b) rotated with respect to the stem portion to produce friction that firmly attaches the head portion to the stem portion.

A novel and improved elbow prosthesis and method of implanting same including a prosthesis system that has a retaining system. The joint prosthesis system can include an implant, and an alignment guide. The alignment guide can include a post member extending through a central axis of rotation in a prosthesis and a drill guide member having a first limiting member for limiting articular surface removal from a joint. The first limiting member can include a recessed guide for positioning the implant.