The acetabulum: The elusive home run of THR

The objective is to describe the current factors for optimizing positioning of the acetabular component in THR. The emphasis in cup placement today is personalizing the component position for each patientʼs anatomy rather than a “one size fits all” (always put the cup in the same position such as 45° inclination and 15° anteversion). To individualize, the arthroplasty requires remembering the operation is on both sides of the joint (combined anteversion) and implanting the cup in the functional plane of that patient, which requires knowledge of the pelvic tilt at surgery and the changes in the spine−pelvic−hip construct between standing and sitting for that patient. To individualize, the cup position will demand higher precision than has been accepted in the past, such as computer navigation, to augment the experience and instinct of the surgeon in performing total hip replacement. In conclusion, acetabular cup placement is an elusive home run because the complexity of its positioning for each patient requires new preoperative planning, and more precise intraoperative positioning.