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 between primary and revision total hip arthroplasty (rTHA). This study compared the time to achieve minimal clinically important difference (MCID) between primary and rTHA.

Methods: We conducted a retrospective analysis comparing 6,671 THAs (6,070 primary and 601 all-cause rTHAs) 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 Short Form 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 total hip arthroplasty (pTHA) demonstrated significantly faster median times than rTHA 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, pTHA continued to achieve MCID significantly faster than rTHA 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).

Conclusions: Across all patient-reported outcome measures, pTHA achieved MCID significantly faster than rTHA, 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 rTHA techniques and perioperative management for improved patient outcomes.

Level Of Evidence: III.