Kinematic versus mechanical alignment in total knee arthroplasty: a systematic review of clinical outcomes, prosthesis utilization, and technological integration

Abstract

Background: Total knee arthroplasty (TKA) is a widely performed orthopedic procedure, yet persistent dissatisfaction among patients has prompted interest in alternative alignment techniques. Kinematic alignment (KA), including its variants-restricted (rKA), individualized (iKA), and functional alignment (FA)-has emerged as a patient-specific alternative to conventional mechanical alignment (MA). Objective: This systematic review aimed to compare KA and MA approaches in TKA, focusing on clinical outcomes, implant models, patient satisfaction, and the influence of surgical technologies. Methods: A comprehensive literature search of PubMed, Embase, Scopus, and Web of Science was conducted for studies published between 2000 and 2025. Eligible studies were assessed for methodological quality using standardized risk of bias tools, and data were extracted on alignment strategy, technology used, demographics, prosthesis design, and outcomes. Results: Thirty-five studies involving over 9,000 patients were analyzed. KA techniques, supported by robotic systems and PSI, yielded higher patient satisfaction (91.2%) and superior PROMs compared to MA (86.3%), with lower revision rates (≤2%). Implants such as Triathlon (Stryker) and Vanguard (Zimmer Biomet) were predominantly used in KA studies. The methodological quality of KA-focused studies was generally higher. Conclusion: Kinematic alignment strategies offer significant advantages in patient-reported outcomes and implant longevity, particularly when combined with advanced surgical technologies. These findings support a shift toward personalized alignment protocols in TKA.