Comparative pain relief and functional outcomes following robotic-assisted versus conventional total knee arthroplasty: a GRADE-assessed meta-analysis with meta-regression of randomized controlled trials

Abstract Although robotic-assisted total knee arthroplasty (RA-TKA) is increasingly adopted for its potential to improve surgical precision, its impact on functional outcomes compared with conventional TKA (C-TKA) remains unclear. Existing syntheses are limited by pooling observational and randomized data, focusing on absolute postoperative scores without evaluating recovery trajectories, and lacking rigorous exploration of heterogeneity. To overcome these limitations, we conducted a methodologically rigorous meta-analysis of randomized controlled trials (RCTs) only, incorporating comprehensive meta-regression, platform-specific subgroup analyses, and assessment of evidence certainty using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. PubMed, Web of Science, Scopus, the Cochrane Library, and Google Scholar ( pages 1–50 ) were comprehensively searched from their inception up to December 27, 2025. Data were pooled using random-effects meta-analysis and Hartung-Knapp adjustments. Meta-regression of different moderators and subgroup analyses by robotic platforms were performed, when feasible, to identify sources of heterogeneity. A total of 24 RCTs encompassing 3,425 patients were included. The pooled analyses demonstrated no significant differences between RA-TKA and C-TKA for change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) function score (MD 0.14; 95% CI − 5.88 to 6.16; p = 0.96), change in functional Knee Society Score (KSS) (MD 0.51; 95% CI − 3.43 to 4.44; p = 0.78), or change in Oxford Knee Score (OKS) (MD 2.07; 95% CI − 6.82 to 10.96; p = 0.51). Although a subgroup analysis revealed a significant improvement in OKS at 6 months only (MD 2.25; p = 0.01), this effect did not reach the minimal clinically important difference (MCID) and was not sustained at other time points. No significant differences were observed for range of motion, change in VAS pain score, KSS satisfaction, or length of hospital stay. Operative time was significantly longer for RA-TKA (MD 22.34 min; 95% CI 13.66 to 31.02; p < 0.01), though this estimate should be interpreted with caution given the very high heterogeneity (I² = 98.53%) and the likelihood that it includes cases performed during the early learning curve of robotic adoption. Trial Sequential Analysis suggested that this finding is unlikely to be attributable to random error, though the required information size was not reached. RA-TKA and C-TKA provide comparable functional improvement, pain relief, and most perioperative outcomes. The most consistent signal is a prolonged operative time with RA-TKA favoring conventional surgery, though the precise magnitude remains uncertain and may be influenced by the learning curve. The certainty of evidence is low to very low across all assessed outcomes, highlighting the need for cautious interpretation. Current evidence does not support the routine adoption of RA-TKA over C-TKA for TKA. Future adequately powered, multicenter RCTs with long-term follow-up and consistent reporting of surgeon experience are required to definitively clarify the role of RA-TKA in contemporary practice.