Primary Total Hip Arthroplasty Achieves Minimal Clinically Important Difference Faster than Revision Total Hip Arthroplasty.

Background: Despite the prevalence of total hip arthroplasty (THA) as a treatment for hip-related conditions, there is limited research directly comparing the patient-reported outcome measures (PROMs) between primary and revision THA. This study compared the time to achieve minimal clinically important difference (MCID) between primary and revision THA.

Methods: We conducted a retrospective analysis comparing 6,671 THAs (6,070 primary and 601 all-cause revision THAs) performed between 2016 and 2022. Patient-reported outcomes were evaluated using preoperative and postoperative scores of Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical, PROMIS Physical Function-10a (PF-10a), and Hip Injury and Osteoarthritis Outcome Score-Physical Function Short-form (HOOS-PS). The time to achieve MCID was assessed using survival curves with and without interval-censoring, and statistical comparisons were performed using log-rank and weighted log-rank tests.

Results: Comparing the time to achieve MCID without interval-censoring, primary THA demonstrated significantly faster median times than revision THA for PROMIS Global Physical (3.3 versus 3.9 months, P < 0.001), PROMIS PF-10a (3.6 versus 6.2 months, P < 0.001), and HOOS-PS (3.1 versus 4.0 months, P < 0.001). Similarly, when using interval-censoring, primary THA continued to achieve MCID significantly faster than revision THA for PROMIS Global Physical (0.23 to 0.24 versus 0.50 to 0.51 months, P < 0.001), PROMIS PF-10a (1.43 to 1.44 versus 3.03 to 3.04 months, P < 0.001), and HOOS-PS (0.87 to 0.87 versus 1.20 to 1.21 months, P < 0.001).

Conclusion: Across all PROMs, primary THA achieved MCID significantly faster than revision THA, irrespective of interval-censoring. These findings underscore the importance of setting realistic postoperative recovery expectations during perioperative patient counseling. Future studies should investigate the factors influencing time to achieve MCID and explore how to enhance revision THA techniques and perioperative management for improved patient outcomes.