A hip prosthesis system (10) comprises a hip-resurfacing femoral component (12) for use with a prepared natural femoral neck, a total-hip-replacement femoral component (14) for insertion into the femur following removal of the natural head and at least in part neck and which is different to the hip-resurfacing femoral component (12), and a common femoral cap (16) which defines a part-spherical articulating surface (82) for engagement with an acetabular cup and which is selectively engagably mountable on the hip-resurfacing femoral component (12) and the total-hip-replacement femoral component (14). A method of intra-operably selecting between a hip resurfacing procedure and a total hip replacement procedure using such a system (10) is also provided.
