Clinical Outcomes of Kinematic Alignment Versus Mechanical Alignment in Total Knee Arthroplasty: An Umbrella Review of Published Meta‐Analyses and Systematic Reviews

ABSTRACT

Mechanical alignment (MA) has long been the standard in total knee arthroplasty, but kinematic alignment (KA) has gained attention as an alternative aiming to restore native knee kinematics; however, comparative evidence on its efficacy and safety remains inconclusive. This study presents an umbrella review comparing KA and MA techniques in total knee arthroplasty. A comprehensive database search was conducted for meta‐analyses published up to January 2023. The original articles included in those meta‐analyses were also retrieved for further analysis. Eleven meta‐analyses, incorporating 30 original studies and 2963 patients, were included. Re‐analysis of controversial outcomes and revision rate data revealed the following: (1) KA was associated with a higher Knee Society Score and Oxford Knee Score; (2) KA yielded lower Western Ontario and McMaster Universities Osteoarthritis Index scores compared with MA; (3) KA resulted in greater flexion range of motion but worse extension range of motion than MA; (4) KA was associated with a higher Forgotten Joint Score‐12; (5) KA resulted in greater femoral valgus and tibial valgus angles, and (6) revision rates were comparable between KA and MA. In patients undergoing total knee arthroplasty, KA demonstrated better clinical outcomes, improved postoperative osteoarthritis‐related symptoms, and greater flexion mobility. Patients in the KA group also reported a higher level of prosthesis “forgetting,” suggesting a more natural postoperative experience. While KA resulted in greater femoral valgus and tibial inversion angles, it may serve as a viable alternative to MA and has the potential to improve patient satisfaction.