Early national comparison of robotic versus conventional hip replacements for arthritis using National Joint Registry data: target trial emulation study

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A UK registry study found similar overall five-year survival and revision outcomes for robotic and conventional hip replacements. Robotic procedures were associated with fewer revisions related to implant malposition, although the observational study cannot rule out residual confounding and notes higher costs.

AbstractObjectivesTo evaluate the early comparative effectiveness of robotic versus conventional total hip replacement (THR) in the UK.DesignTarget trial emulation study.SettingPublic and private hospitals using data from the National Joint Registry of England, Wales, Northern Ireland, the Isle of Man, Guernsey, and Jersey.Participants666 283 THRs performed between 2018 and 2024; 656 080 were conventional THRs and 10 203 were robotic THRs.Main outcome measuresFive year THR implant survival (mean 2.5 year follow-up), all cause revision risk, cause specific revision risk, malpositioning revision risk, intraoperative complications, and patient survival up to five years. Kaplan-Meier survival analysis, Cox proportional hazards regression, and Fine and Gray models were used. Propensity score matching created comparable treatment groups to estimate the average treatment effect in the treated population.ResultsThe five year implant survival of the matched conventional and robotic THR groups was 98.8% (95% confidence interval (CI) 98.6% to 99.0%) and 98.8% (CI 98.3% to 99.1%), respectively, with no difference in revision risk between groups (hazard ratio 0.96, 95% CI 0.75 to 1.22; P=0.73). Cause specific revision risk and intraoperative complication risks did not differ between groups. However, a significantly lower risk of revisions related to implant malposition (dislocation, leg length discrepancy, and malalignment) was observed in the robotic group (hazard ratio 0.53, 95% CI 0.30 to 0.93; P=0.03). The five year patient survival of the matched conventional and robotic THR groups was 96.3% (95% CI 95.8% to 96.8%) and 96.2% (95.2% to 97.0%), respectively, with no difference in all cause mortality risk (hazard ratio 1.12, 95% CI 0.95 to 1.34; P=0.17).ConclusionsNo significant differences were found in overall THR or patient survival, cause specific revision, or intraoperative complication risks between robotic and conventional groups. Robotic THR was associated with a lower revision risk from causes related to implant malpositioning. However, the possibility of unmeasured and residual confounding cannot be ruled out owing to the observational design. These results highlight the importance of careful evaluation of robotic technology in publicly funded healthcare systems because of the substantially higher capital and procedural costs.