CORR - 2026-06-03 - Journal Article
Is Robotic-assisted THA Associated With Decreased Risk of All-cause Revision or Revision for Dislocation? An Analysis of the American Joint Replacement Registry.
Kirchner GJ, Riley C, Jimenez E, Stambough JB, Nikkel LE
Topics
Key Takeaway
Robotic-assisted THA was associated with a 50% reduction in revision for dislocation at 2 years (HR 0.5, 95% CI 0.3–0.9) compared to conventional THA, but no difference in all-cause revision (HR 0.9, 95% CI 0.7–1.1).
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Summary
This AJRR-Medicare linked registry study asked whether robotic-assisted THA reduces all-cause revision or revision for dislocation at 2 years in Medicare-age patients (≥65 years) undergoing primary elective THA from 2017–2021. Mixed-effect Cox regression controlling for age, CCI, LOS, sex, anesthesia type, race, surgeon, and institution showed no difference in all-cause revision (1.9% robotic vs. 2.1% conventional, HR 0.9, p=0.42). Revision for dislocation was significantly lower with robotic assistance (0.3% vs. 0.6%, HR 0.5, p=0.03).
Key Limitation
Surgical approach, cup abduction/anteversion angles, and implant-specific data are not captured in the registry, making it impossible to confirm that the dislocation benefit is attributable to improved component positioning rather than unmeasured surgeon or patient selection factors.
Original Abstract
BACKGROUND
Robot-assisted THA is becoming more common, and evidence suggests that robot assistance improves the accuracy of acetabular cup positioning. By means of reducing implant malpositioning, robot-assisted THA has been proposed as a method to reduce the risk of revision surgery and particularly revision due to dislocation. However, this has not yet been explored using an arthroplasty registry.
QUESTIONS/PURPOSES
(1) In a dataset drawn from the American Joint Replacement Registry (AJRR) and its Medicare claims data linkage, after controlling for confounding variables, is robot-assisted THA associated with a decreased risk of all-cause revision at minimum 2-year follow-up? (2) After controlling for confounding variables, is robot-assisted THA associated with a decreased risk of revision for dislocation at minimum 2-year follow-up?
METHODS
The AJRR and its Medicare claims data linkage were used to create a retrospective comparative study of patients aged 65 years or older who underwent primary elective robot-assisted THA (n = 113,477) or conventional THA (n = 10,988) between 2017 and 2021. All patients within the AJRR who had undergone primary THA and had complete records with respect to robot data were included. The AJRR was selected for this study because of its Medicare linkage, and therefore follow-up data are considered near complete. Both cohorts had the same mean age (74 ± 6 years; p = 0.15) and the same proportion of females (60% [67,903 of 113,447] for conventional THA versus 60% [6540 of 10,988] for robot-assisted THA; p = 0.51). Mixed-effect Cox regression models were used to determine the hazard of all-cause revision and revision for dislocation at 2 years. Variables included within these models were age, Charlson comorbidity index (CCI), length of stay (LOS), sex, anesthesia type, and race. Surgeon and institution were controlled as the random effect within these models.
RESULTS
After controlling for confounding variables, the risk of all-cause revision at 2 years did not differ between robot-assisted THA and conventional THA (1.9% [208 of 10,988] versus 2.1% [2357 of 113,477], HR 0.9 [95% confidence interval (CI) 0.7 to 1.1]; p = 0.42). Revision for dislocation was lower in robot-assisted THA (0.3% [35 of 10,988]) compared to conventional THA (0.6% (689 of 113,477), HR 0.5 [95% CI 0.3 to 0.9]; p = 0.03).
CONCLUSION
Robot-assisted THA did not demonstrate a difference in all-cause revision at 2 years, but robot-assisted THA was associated with a reduced risk of revision for dislocation compared to conventional THA. This study demonstrates that robotic assistance is a potentially useful adjunct during THA to decrease the risk of early revision for dislocation. In clinical scenarios where early dislocation might be a concern, robot-assisted THA might be considered a means to mitigate this risk. However, until or unless robot assistance demonstrates clear improvement regarding revision-free implant survival, surgeons should remain cautious of widespread adoption of this technology.
LEVEL OF EVIDENCE
Level III, therapeutic study.