Total Hip Arthroplasty Functional Outcomes Are Independent of Acetabular Component Orientation When a Polyethylene Liner Is Used

Background: This study evaluated patient-reported outcomes in patients undergoing primary total hip arthroplasty with a polyethylene liner to determine the influence of cup orientation and other variables on patient-reported outcomes. Methods: A total of 477 cases were prospectively monitored through average 4.7 years follow-up. Cup position was measured on pelvis radiographs. Patients completed the Western Ontario and McMaster Universities Osteoarthritis Index and Short Form 12 Health Survey questionnaires. Results: Average cup abduction was 43.1 degrees +/- 7.5 degrees and anteversion was 13.3 degrees +/- 7.5 degrees. Three hundred cups were within the target zone. All outcomes' improvement from baseline and cup position was not an independent risk factor for the Western Ontario and McMaster Universities Osteoarthritis Index or Short Form 12 Health Survey improvement. Conclusion: Accurate cup orientation may not be critical to maximizing patient-perceived outcomes if the combined anteversion is within a normal range, the hip joint is properly balanced, and a polyethylene liner is coupled with a metal or ceramic femoral head. (C) 2016 Elsevier Inc. All rights reserved.