High Satisfaction, Modest Differences: A Comparative Cohort Study of Robotic-Assisted and Conventional Total Hip...

Background/Objectives: Robotic-assisted total hip arthroplasty (raTHA) improves the accuracy and reproducibility of acetabular component positioning compared with conventional THA (cTHA), but whether this translates into superior patient-reported outcomes and satisfaction remains debated. Methods: A retrospective comparative cohort study was performed, including all patients who underwent primary raTHA with the Mako system at our institution (September 2024-May 2025) and an equal-sized control group recruited consecutively from an alphabetically ordered list of 172 eligible cTHAs, starting from a randomly selected letter (August 2022-January 2025), with a minimum follow-up of one year. Treatment allocation was determined by insurance coverage. The postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was the primary outcome; the Visual Analog Scale (VAS), modified Harris Hip Score (mHHS) and Forgotten Joint Score-12 (FJS-12) were secondary outcomes, and an overall satisfaction rating and willingness to undergo the surgery again were also recorded. Results: Ninety-three raTHA and 93 cTHA patients were analyzed. Follow-up was longer in the cTHA group (35.6 vs. 15.5 months; p < 0.001). Postoperative WOMAC (10.5 vs. 14.4; mean difference -3.8 points, 95% CI -7.4 to -0.2) and mHHS (86.9 vs. 84.7; mean difference 2.2 points, 95% CI -0.9 to 5.4) differed in rank-based comparisons, favoring raTHA (Mann-Whitney U test, p = 0.020 and p = 0.030, respectively). Point estimates were below the selected clinical-relevance thresholds, but the confidence intervals did not exclude clinically relevant differences; improvement from baseline did not differ between groups. There were no significant differences in VAS, FJS-12, overall satisfaction (9.32 vs. 9.31) or willingness to undergo surgery again (96.8% vs. 97.8%). Conclusions: Given insurance-based allocation, unequal follow-up and unadjusted analyses, robotic-assisted THA was associated with small differences in postoperative WOMAC and mHHS, whose point estimates were below the selected thresholds, although clinically relevant differences cannot be excluded; there were no differences in improvement, pain, joint awareness or satisfaction, which was very high in both groups. These findings do not establish a causal effect of robotic assistance; prospective randomized studies are needed.