Time to Achieve Minimal Clinically Important Difference (MCID) in Robotic versus Manual Total Knee Arthroplasty: A Comparative Analysis.

Abstract

Background: Robotics in arthroplasty remains controversial due to the uncertainty of clinical outcomes in robotic total knee arthroplasty (rTKA). This study aimed to compare the time to achieve the minimal clinically important difference (MCID) between rTKA and manual TKA (mTKA).

Methods: A total of 726 TKAs (416 robotic and 310 manual) were analyzed. We conducted a retrospective analysis of 726 TKAs performed between 2019 and 2022. Patient-reported outcomes were assessed using the Patient-Reported Outcomes Measurement Information System (PROMIS) Global Physical, PROMIS Physical Function-10a (PF-10a), and Knee Injury and Osteoarthritis Outcome Score-Physical Function Short-form (KOOS-PS) scores, both preoperatively and postoperatively. Survival curves, accounting for interval censoring, were utilized to evaluate the time to achieve MCID. Statistical comparisons between groups were made using log-rank and weighted log-rank tests.

Results: Comparing time to achieve MCID without interval censoring, the median time for rTKA was significantly lower than mTKA for PROMIS Global Physical (3.5 versus 3.7 months, P = 0.032) and KOOS-PS (3.7 versus 5.3 months, P = 0.002), but similar for PROMIS PF-10a (6.0 versus 6.7 months, P = 0.16). Notably, interval censoring showed similar times to achieve MCID for rTKA and mTKA in PROMIS Global Physical (0.53 to 0.54 versus 1.23 to 1.24 months, P = 0.31), PROMIS PF-10a (3.03 to 3.03 versus 2.17 to 2.17 months, P = 0.89), and KOOS-PS (1.47 to 1.47 versus 2.17 to 2.17 months, P = 0.27).

Discussion: Using time to MCID methodology, the median time to achieve MCID did not differ by surgical technique. The present study offers valuable patient-centric insights into preoperative expectations management and patient education. Further prospective studies with more granular Patient-Reported Outcomes Measurement (PROM) collection are needed to evaluate the true effectiveness of robotics in arthroplasty.