Abstract
To compare the early clinical efficacy and postoperative implant alignment between NATON robotic-assisted unicompartmental knee arthroplasty (RA-UKA) and conventional UKA (C-UKA) in treating severe medial compartment knee osteoarthritis (OA). This retrospective matched cohort study included 40 RA-UKA and 40 C-UKA patients, matched 1:1 by age, gender, and surgical site et al. Primary outcomes included operative time, intraoperative blood loss, and patient-reported outcome measures (PROMs): knee society score (KSS), Oxford knee score (OKS), visual analogue scale (VAS) for pain, and forgotten joint score (FJS). Radiological assessments included coronal/sagittal angular deviations of femoral/tibial components, hip-knee-ankle (HKA) angle, and Kennedy zone distribution. The follow-up time was 15.4 ± 1.6 months. Operative time was significantly longer in the RA-UKA group (95.8 ± 6.8 min vs. 75.3 ± 6.5 min, P < 0.001). No significant differences were observed in KSS score, OKS score, or intraoperative blood loss between groups (all P > 0.05). RA-UKA achieved significantly better subjective PROMs, with lower VAS score (1.97 vs. 2.5, P = 0.012, Cohen’s d = − 0.60) and higher FJS score (86.9 vs. 84.3, P = 0.025, Cohen’s d = 0.50). The RA-UKA group had smaller femoral component coronal alignment deviation (2.39 ± 1.41° vs. 5.79 ± 1.15°, P < 0.001, Cohen’s d = − 2.46) and flexion alignment deviation (3.3° (2.9–4.0) vs. 6.5° (5.9–7.1), P < 0.001, Cohen’s d = − 0.78). No significant differences were observed in tibial component coronal deviation and posterior tibial slope(PTS) deviation between two groups (all P > 0.05). Correlation analysis revealed weak negative correlations between FJS score and femoral coronal/flexion deviations (all P < 0.05). VAS score was weakly positive correlated with PTS deviation (ρ = 0.240, P = 0.032) and moderately positive correlated with femoral coronal deviation (r = 0.311, P = 0.005). No serious complications occurred in either group during follow-up. The NATON RA-UKA achieved more accurate early implant positioning than C-UKA, while short-term clinical outcomes were generally comparable between groups.
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Data availability
All data supporting the findings of this study are available within the paper and its Supplementary Information. Microsatellite primer sequences are provided in Supplementary Table, along with original reference describing the microsatellites used in this study.
References
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Funding
This study was funded by the Suining Health Science and Technology Plan Project (Municipal Health Commission Project) in 2025 (Project number: 25ZDJB04). The funders had no role in the collection, analysis, or interpretation of the data or in the preparation of the manuscript.
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YL and JW contributed equally to this work as co-first authors. YL contributed to the article writing and data collection. XP and KH contributed to some imaging data and surgery. JW and GJ-S contributed to part of the statistics of the article. YL and XP directed the writing of the article. XP designed the study and was responsible for the paper.
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This study was approved by the Ethical Committee of Suining Central Hospital (KYLLKS20240207). Due to the retrospective nature of the study, informed consent was waived by the Ethics Committee of Suining Central Hospital.
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Li, Y., Wu, J., He, K. et al. NATON robotic-assisted unicompartmental knee arthroplasty achieves superior radiological alignment and comparable one-year functional outcomes to conventional surgery. Sci Rep (2026). https://doi.org/10.1038/s41598-026-48561-9
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DOI: https://doi.org/10.1038/s41598-026-48561-9
