Early revision rate in robotic-assisted versus conventional total knee arthroplasty: a prospective cohort study 2021-2023 from the Finnish Arthroplasty Register.

BACKGROUND AND PURPOSE: Robotic-assisted total knee arthroplasty (rTKA) has been proposed to improve component positioning but evidence on its effect on implant survival is limited. We aimed to compare implant survival between rTKA and conventional total knee arthroplasty (cTKA) overall and due to peri-prosthetic joint infection (PJI). METHODS: We included all rTKAs performed in Finland from April 2021 until May 2023, all implanted with Triathlon TKA using MAKO robotic-arm assist. Propensity score matching was used to form a control group with similar characteristics for the same time period. Primary survival endpoint was first revision due to any cause within 12 months after the index surgery. PJI and non-PJI revisions were considered secondary outcomes. Kaplan-Meier (KM) analysis and Cox proportional hazards regression were used to assess implant survival and between-group contrasts hazard ratios (HR) with 95% confidence intervals (CIs), respectively. RESULTS: 1,318 fixed bearing rTKAs were compared with a control group of 1,318 cTKAs. Revision-free survival at 12 months after index surgery did not differ between groups. KM estimates were 99.1% (CI 98.5-99.7) for rTKA and 98.6% (CI 98.0-99.3) for cTKA with HR 0.61 (CI 0.28-1.34). The rTKA group demonstrated better PJI-free survival at 12 months (HR 0.29, CI 0.10-0.90). Overall, PJI was the most common reason for revision. At the end of available follow-up, the estimated overall survival was 97.7% (CI 94.9-100.0) for rTKA and 97.9% (CI 96.6-99.2) for cTKA. CONCLUSION: No difference in all-cause revision risk was observed between rTKA and cTKA groups. However, within the first 12 months, fewer revisions due to PJI occurred in the rTKA group.