# Time to Achieve a Minimal Clinically Important Difference After Total Hip Arthroplasty: A Retrospective Cohort Comparison of Robotic-Assisted, Navigation-Assisted, and Conventional Techniques

## TL;DR

This study compares recovery times after hip replacement using robotic, navigation, and conventional techniques, finding no major patient-perceived benefit from advanced technologies.

## Contribution

The study evaluates the impact of robotic and navigation-assisted hip replacement on recovery time to a clinically meaningful improvement, using both anchor- and distribution-based thresholds.

## Key findings

- Robotic-assisted THA reached MCID 33.5% faster than conventional THA using distribution-based thresholds.
- Navigation-assisted THA showed no significant difference in MCID time compared to conventional THA.
- Anchor-based MCID showed no significant differences in recovery times across the three techniques.

## Abstract

Technological advancements in total hip arthroplasty (THA), including robotic-assisted (RA-THA) and navigation-assisted (NA-THA) techniques, aim to improve outcomes. However, impact on recovery timing remains unclear. This study examined whether these technologies reduce the time to reach the minimal clinically important difference (MCID) on the Hip Disability and Osteoarthritis Outcome Score for Joint Replacement compared with conventional THA.

This retrospective study analyzed osteoarthritic THA patients (01/2020-04/2023) who completed preoperative and postoperative Hip Disability and Osteoarthritis Outcome Score for Joint Replacement questionnaires. The exclusion criteria included bilateral procedures or revision within 1 year. MCID was defined using anchor-based (23 points) and distribution-based thresholds (7.6 points). Multivariable interval-censored accelerated failure time models assessed time to MCID.

Among the 1395 patients, 181 (12.9%) underwent RA-THA, 754 (54.1%) underwent NA-THA, and 460 (33.0%) underwent conventional THA. Anchor-based MCID rates were 65.2%, 63.4%, and 66.5%, respectively (P > .05), with median times of 38.9, 48.4, and 45.1 days. Neither RA-THA (time ratio [TR] = 0.86, 95% confidence interval [CI]: 0.63-1.18, P = .347) nor NA-THA (TR = 1.07, 95% CI: 0.87-1.32, P = .502) significantly affected time to MCID vs conventional distribution-based thresholds yielded higher MCID rates (93.9%, 88.9%, 89.8%; P > .05) with median times of 8.6, 11.4, and 12.9 days, respectively. RA-THA reached MCID 33.5% faster than conventional THA (TR = 0.66, 95% 26 CI: 0.52-0.86, P = .002) and 24.3% faster than NA-THA (TR = 0.76, 95% CI: 0.60-0.95, P = .019), while NA-THA showed no significant difference vs conventional THA (TR = 0.88, 95% CI: 0.74-1.04, P = .140).

Anchor-based MCID demonstrated comparable recovery times across RA, NA, and conventional THA, suggesting no patient-perceived advantage with technology. Distribution-based thresholds indicated RA-THA achieved faster statistically significant improvement, though the relevance remains uncertain.