Functional alignment in robotic total knee arthroplasty provides favourable outcomes and minimal early revisions: A systematic review and meta-analysis

Abstract

Purpose: Functional alignment (FA) has emerged as a personalised alignment strategy in total knee arthroplasty (TKA), enabled by robotic-assisted technology. Although early clinical results are encouraging, evidence remains heterogeneous and long-term safety is uncertain. This systematic review aimed to evaluate functional outcomes, and early revision risk of robotic-assisted TKA performed under FA principles with a minimum follow-up of two years. Methods: This review was conducted according to PRISMA guidelines and registered in PROSPERO (CRD420251134340). PubMed/MEDLINE and Scopus were searched up to August 2025. Eligible studies included adult patients undergoing robotic-assisted primary TKA with FA, reporting outcomes at ≥2 years' follow-up. Data on demographics, robotic system, implant type, patient-reported outcome measures (PROMs), range of motion (ROM), complications, and revision rates were extracted. Risk of bias was assessed using ROB 2 and ROBINS-I. A random-effects single-arm meta-analysis of pooled proportions was performed for early aseptic revision risk. Results: Twenty studies (5155 TKAs) were included, with a weighted mean follow-up of 2.5 years. All procedures were performed using the image-based robotic system. Postoperative PROMs were consistently high: Knee Society Score (KSS) Knee 92.4–94.5, KSS Function 91.4–93.4, and FJS 74.8–77.5. Kujala scores indicated minimal anterior knee pain (88.1–93.2). ROM improved from a mean preoperative flexion of 119.3° to 123°–124.8°. Complications were infrequent, most commonly stiffness requiring manipulation under anaesthesia. Across all cohorts, 18 aseptic revisions were reported (pooled proportion 0.35%, 95% CI 0.23–0.55). The single-arm meta-analysis of pooled proportions showed a negligible pooled early revision risk (rounded to 0.00; 95% CI 0.00–0.01; I² = 0%). Outcomes were comparable across age, gender, fixation type, and implant constraint, although obese patients accounted for all mechanical failures. Conclusion: Robotic-assisted TKA performed under FA principles yields favourable short- to mid-term functional outcomes and a low rate of early aseptic revision. Level of Evidence: Level III, systematic review and meta-analysis.