Robotic-assisted total knee arthroplasty for severe fixed valgus deformity: a systematic review of alignment restoration, soft tissue balancing strategies, and clinical outcomes.

Managing moderate-to-severe fixed valgus deformities in total knee arthroplasty (TKA) is technically demanding due to lateral compartment bony hypoplasia, contracted lateral soft tissues, and medial collateral ligament laxity. While conventional workflows often require extensive manual ligamentous releases, robotic-assisted TKA (RA-TKA) offers real-time digital gap balancing. This systematic review evaluates the clinical and radiographic efficacy of RA-TKA specifically isolating the moderate-to-severe fixed valgus morphotype. A systematic search of PubMed, Scopus, Google Scholar, and Cochrane CENTRAL was conducted from 27th of May 2026 to 1st of June 2026. The study was prospectively registered on PROSPERO, and clinical studies evaluating primary RA-TKA for fixed valgus deformities (at least 100, or Krackow Type II or III) were included. Methodological quality was assessed using the ROBINS-I tool and JBI Critical Appraisal Checklist. Thirteen studies comprising 1,787 robotic-assisted TKAs were included. Improvements from preoperative to postoperative coronal alignment were consistently achieved, with mean postoperative hip-knee-ankle angles restored to within 10-30 of surgical targets and low outlier rates (<20% across robotic cohorts compared to up to 42.3% in manual controls). Functional Alignment cohorts consistently achieved 0% manual soft-tissue release rate. Conversely, Mechanical Alignment (MA) cohorts required selective lateral releases (primarily the iliotibial band and popliteus tendon) in 38.5% to 71.4% of cases. Robotic-assisted TKA is a safe and highly precise tool for managing the complex valgus morphotype. It provides excellent coronal alignment restoration and facilitates a major de-escalation of surgical trauma, allowing surgeons to achieve stability with standard, lower-constraint implants. Level of Evidence: Level IV.