Functional Versus Mechanical Alignment in Robotic-Assisted Primary Total Knee Arthroplasty: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials

Functional alignment (FA) in robotic-assisted total knee arthroplasty (TKA) aims to individualize component positioning and soft-tissue balance.However, whether these technical differences improve patient-reported outcomes compared with mechanical alignment (MA) remains uncertain.A systematic review and meta-analysis of randomized controlled trials comparing FA and MA in primary robotic-assisted TKA was conducted.MEDLINE, Embase, and CENTRAL were searched, supplemented by trial registries and citation searching.The primary outcome was the Forgotten Joint Score (FJS) at approximately 12 months.Secondary outcomes included other patient-reported measures, soft-tissue release, radiological alignment, and complications.Risk of bias was assessed using RoB 2, and evidence certainty using Grading of Recommendations Assessment, Development and Evaluation (GRADE).Randomeffects meta-analysis was performed where appropriate, using restricted maximum likelihood estimation and Hartung-Knapp inference.Of 406 database records, 11 reports representing seven independent randomized trial families were included.A definitive 12-month FJS meta-analysis was inappropriate because of methodological and reporting heterogeneity.Two randomized comparisons contributed to the early FJS analysis (≤six months).The pooled mean difference favoured FA by 8.62 points, but the Hartung-Knapp 95% confidence interval was wide (-16.90 to 34.14; I²=0%).A DerSimonian-Laird sensitivity analysis yielded a narrower interval (95% CI 4.56-12.68).FA was associated with fewer soft-tissue releases across several included trials.Radiological findings generally favoured preservation of individualized alignment, while patient-reported outcomes showed no consistent clinically important improvement.Serious complications and revisions were uncommon, and certainty of evidence for principal outcomes was very low.Robotic FA reduces the requirement for soft-tissue release and produces distinct radiological alignment patterns compared with MA.However, current randomized evidence does not establish superior patientreported outcomes.Early FJS findings remain uncertain because of the limited evidence base and imprecision.Larger randomized trials with standardized protocols and longer follow-up are required.