An instrument (10) for positioning a hollow cup component (40) of an orthopaedic joint prosthesis. The instrument includes an insertion end section (12) a handle end section (14) opposite the insertion end section and a shaft (16) coupling the insertion end section to the handle end section. The insertion end section includes a cam wheel (32) and a plurality of expanding pieces (30) coupled to the cam wheel such that when the cam wheel is rotated in one direction the expanding pieces expand out in a radial direction and frictionally engage an inner surface of the hollow cup component.
