Robotic-assisted total knee arthroplasty demonstrates superior early functional outcomes compared with conventional total knee arthroplasty: a quasi-randomised controlled trial

Abstract Background Robotic-assisted total knee arthroplasty (TKA) has gained popularity over the last decade, with claimed advantages in implant positioning accuracy and soft-tissue balance. Whether these technical advantages translate into better clinical outcomes for patients remains debated. This investigation compared 1-year patient-reported outcomes between robotic-assisted and conventional TKA performed within the same institution but following structurally different surgical workflows. Methods This quasi-randomised controlled trial enrolled patients who underwent primary TKA at the Department of Orthopaedic and Trauam Surgery of the Eifelklink St. Brigida (Simmerath, Germany) between 2022 and 2025. Group allocation was determined by surgeon assignment through the institutional digital scheduling system. All patients received the same implant (Smith & Nephew Legion Genesis II, posterior-stabilised). Robotic-assisted procedures were performed using the CORI Robotic System (Smith & Nephew, UK) following a four-dimensional personalised alignment workflow (coronal, sagittal, transversal and balancing) guided intraoperatively by the Knee Balancing Score (KBS). Conventional procedures followed a femur-first technique with adjusted mechanical alignment. Outcomes included WOMAC total and subscores, visual analogue scale (VAS), Tegner activity score and a dedicated functional questionnaire, all assessed at 1-year follow-up. Results A total of 845 patients were included (robotic-assisted: n = 390; conventional: n = 455). At 1-year, 383 and 445 patients completed follow-up, respectively. The two groups were comparable at baseline. The robotic-assisted cohort showed significantly better results across WOMAC and related subscales ( P < 0.001), VAS ( P < 0.001), Tegner ( P < 0.001), functional and satisfaction items, including walking distance and knee stability. No difference was found in the use of walking aids. Conclusions Robotic-assisted TKA was associated with superior functional and patient-reported outcomes at the 1-year follow-up. The clinical benefit observed is likely not attributable to robotic precision alone, but reflects the structured, personalised intraoperative workflow that robotic assistance enables. Trial Registry German Registry of Clinical Trials (ID DRKS00030614).