A system for securing a prosthesis in a bone includes a reference anchor (16) for insertion into a cavity of a bone to define a reference point during prosthesis implantation, the reference anchor including a body having a mating feature and a gripping projection for engaging an inner surface of the bone cavity. The system also includes a stem (22 40 18) having a terminal end (28 52 122) adapted to mate with the mating feature of the reference anchor such that the stem is disposed at a desired position relative to the reference point.