Superior Transverse Atraumatic Reconstruction Total Hip Arthroplasty Achieves Similar Satisfaction and Minimal Clinically Important Differences When Compared to the Direct Anterior Approach: A Propensity Score Matched Study with Two-Year Outcomes.

Background: Numerous studies comparing the direct anterior (DAA) and postero-lateral approach (PLA) in total hip arthroplasty (THA) have been inconclusive, mostly demonstrating earlier recovery with DAA, with no differences in outcomes by one year. However, there are limited studies comparing the DAA with the superior transverse atraumatic reconstruction (STAR) THA, which is a type of PLA. This study aimed to compare the 2-year follow-up patient-reported outcome measures (PROMs), satisfaction, and complication rates between DAA and STAR THA.

Methods: A retrospective analysis of all primary THAs performed (January 2018 to December 2022) at a high-volume tertiary hospital was conducted. The study included patients > 60 years at the time of THA with minimum 2-year outcomes of Oxford Hip Score (OHS), Western Ontario and McMaster University Arthritic Index (WOMAC), Short Form 36 Health Survey (SF-36) subscale and summative (physical component score [PCS]/mental component scores [MCS]), patient satisfaction, and expectation fulfillment scores. The DAA THA was performed with either fluoroscopic or robotic assistance, whereas the STAR THA was performed manually. Logistic regressions were performed to estimate propensity scores, followed by greedy matching in a 1:1 ratio to establish the DAA and STAR groups. Parametric and non-parametric statistical tests were used to compare postoperative scores and the proportion attaining a minimum clinically important difference (MCID). A total of 132 DAA THA were successfully matched with 132 STAR THA.

Results: The DAA group demonstrated significantly higher scores in 2-year postoperative OHS (P = 0.0140), WOMAC stiffness (P = 0.0455), physical function (P = 0.0125), SF-36 physical function (P = 0.00537), general health (P = 0.0495), social function (P = 0.0266), PCS (P = 0.0478), and MCS (P = 0.0482). There was no difference in MCID attainment, patient satisfaction, or expectation fulfillment scores noted.

Conclusion: While technology-assisted DAA THA demonstrated better functional outcomes at two years, its clinical relevance may be limited, as manually performed STAR THA also attained MCID thresholds and yielded high patient satisfaction rates without additional complications. This suggests that slightly lower functional scores do not compromise overall THA success.