Functional alignment robotic-assisted TKA improves clinical outcomes compared with conventional mechanical alignment TKA: A single-surgeon randomised controlled non-inferiority trial with 2-year follow-up
In brief
Robotic functional-alignment knee replacement yields modestly better scores at two years
In a single-surgeon randomized trial of 163 patients, knees implanted with robotic-assisted functional alignment showed slightly higher Knee Society, Oxford, and pain scores through two-year follow-up compared with conventional mechanical alignment. The advantages were statistically significant but small (effect sizes up to 0.21), suggesting a modest clinical edge that warrants further confirmation in larger, multi-surgeon studies.
- Journal
- Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA (Q1)
- Published
- 11 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Remco Coenen, Arne Peeters, Peter Bollars, Dinesh Nathwani, Ali Albelooshi, Max Til Ettinger, et al.
- PMID
- 42726923
- DOI
- 10.1002/ksa.70589
Why clinicians should know about it
- Picked for Orthopedics and Sports Medicine (top studies of the week, 13 September 2026): Functional alignment robotic‑assisted TKA vs conventional MA‑TKA RCT
Abstract
PURPOSE: Functional alignment (FA) has emerged as an alternative to mechanical alignment (MA) in total knee arthroplasty (TKA), supported by robotic assistance to enhance precision and soft‑tissue preservation. Evidence comparing FA performed with robotic assistance to conventional MA‑TKA across mid‑term patient‑reported outcomes measures (PROMs) remains limited. This randomised controlled trial evaluated differences in recovery trajectories and 2‑year knee‑specific outcomes between FA‑RATKA and MA‑CTKA. METHODS: This study reports the predefined primary 2-year outcomes of a prospective randomised controlled non-inferiority trial including 180 patients (FA-RATKA, n = 81; MA-CTKA, n = 82), of whom 163 completed follow-up. Assessments were performed preoperatively and at 3-months, 1- and 2-years using validated PROMs: Knee Society Score (KSS) subdomains, Oxford Knee Score (OKS), Forgotten Joint Score (FJS-12), VAS pain, EQ-5D-5L (index and VAS), Lower Extremity Activity Scale (LEAS), and overall satisfaction. Mixed-effects models evaluated group, time, and Group × Time interactions, adjusting for age, BMI, and soft-tissue release. Effect sizes (r) were calculated to contextualise clinical relevance. RESULTS: FA-RATKA demonstrated more favourable knee-specific outcomes across follow-up, with significant Group × Time interactions for KSS Function (F(3,679) = 6.970, p < 0.001; r = 0.173), KSS Satisfaction (F(3,679) = 10.892, p < 0.001; r = 0.214) and KSS Symptoms (F(3,679) = 4.425, p = 0.004; r = 0.138). FA-RATKA also showed more favourable OKS trajectories (F(3,679) = 8.053, p < 0.001; r = 0.185), lower VAS pain (F(3,679) = 8.339, p < 0.001; r = 0.188), and higher EQ-5D index scores (F(2,515) = 5.227, p = 0.006; r = 0.141). Categorical satisfaction favoured FA-RATKA at early follow-up (F(2,503) = 3.491, p = 0.031; r = 0.117). Effect sizes ranged from r = 0.117 to 0.214, corresponding to small to small-medium magnitudes. CONCLUSIONS: In this prospective, randomised, single-surgeon study, several knee-specific patient-reported outcomes demonstrated modest but statistically supported differences at 2-year follow-up, with consistently higher values in the FA-RATKA group. LEVEL OF EVIDENCE: Level I, randomised controlled trials with adequate statistical power to detect differences (narrow confidence intervals) and follow up >80%, as per the KSSTA guidelines.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.