An impactor for positioning and inserting an acetabular cup into an acetabulum of a pelvis during hip arthroplasty is described. The impactor includes a guide element mounted to an elongated body and including first and second openings aligned with each other to define an axial passage. The first and second openings and the axial passage receive a guide pin therethrough that is pinned in a fixed position to the pelvis. The guide element provides a mechanical orientation guide which restricts an angular orientation of the impactor relative to the guide pin when the guide pin is pinned in the fixed position relative to the pelvis and received through the first and second openings of the guide element. Centering the openings of the guide element relative to the guide pin in the fixed position accordingly achieves a desired orientation of the impactor within a predetermined angular tolerance.
