An instrument for positioning a hollow cup component of an orthopaedic joint prosthesis. The instrument includes an insertion end section, a handle end section opposite the insertion end section, and a shaft coupling the insertion end section to the handle end section. The insertion end section includes a cam wheel and a plurality of expanding pieces 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.
