Kinematic and mechanical alignments in total knee arthroplasty: A meta-analysis with ≥ 1-year follow-up

Background: Kinematic and mechanical alignment outcomes in total knee arthroplasty remain controversial. This study compared the clinical and radiological outcomes of total knee arthroplasty using kinematic and mechanical alignments. Methods: We systematically searched PubMed, EMBASE, Web of Science, and Cochrane Library databases for randomized controlled trials and cohort studies published before November 2022. The data of interest were extracted and analyzed using Review Manager V.5.4. Results: Nineteen randomized controlled trials and cohort studies involving 880 kinematic alignment total knee arthroplasties and 965 mechanical alignment total knee arthroplasties were included. In this meta-analysis, the kinematic alignment group achieved better knee joint function scores, including the Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, and Knee Society Score, and better flexion angles. No statistical differences were detected in the Western Ontario and McMaster Universities Osteoarthritis Index, extension angle, Forgotten Joint Score, European Quality of Life five-dimension measure, hip-knee-ankle angle, or complications between the kinematic and mechanical alignment groups. Conclusion: This meta-analysis indicated that kinematic alignment total knee arthroplasty provides clinical benefits in terms of the Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, Knee Society Score (knee), Knee Society Score (function), and better flexion angles. In addition, kinematic alignment total knee arthroplasty led to similar clinical outcomes as mechanical alignment total knee arthroplasty without increasing complications. Systematic review registration: http://www.crd.york.ac.uk/PROSPERO/CRD42022373227. (c) 2023 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.