Accurate Restoration of the Center of Rotation of the Hip Joint Based on Preoperative Planning Is Not Associated with Improved Clinical Outcomes

Abstract

One of the main objectives of total hip arthroplasty (THA) is to recreate the center of rotation (COR). Accurate reconstruction of the COR is suggested to be within 5 mm of its anatomical location. The goal of our study was to assess whether accurate reconstruction of the COR, based on preoperative planning, is associated with improved clinical outcomes. The study population consisted of patients who underwent THA at our institution between August 2018 and May 2020. All patients underwent preoperative digital templating. The position of the predicted COR was compared to its actual postoperative position. Patients were subsequently stratified into two subgroups based on the difference between the distance of the predicted COR and the reconstructed COR, over or under 5 mm. A 12-Item Short Form Health Survey (SF-12) and visual analogue scale (VAS) were taken for each patient. 90 patients were included in this study. 60 patients (66%) had their COR reconstructed within 5 mm of preoperative planning, whereas for 30 patients (33%), reconstruction was outside of 5 mm of preoperative planning. Between the two cohorts, no significant difference existed in the physical component summary (PCS) (p = 0.33), the mental component summary (MCS = 0.16), or the visual analogue scale (VAS) (p = 0.12). The accurate restoration of COR based on preoperative planning is not associated with improved clinical outcomes. During postoperative evaluation, surgeons should feel confident if the COR is slightly greater than 5 mm of preoperative limitations.