Functional alignment: Defined personalized alignment strategy with promising outcomes and room for improvement

Functional alignment (FA) has emerged as a patient-specific alternative to traditional alignment philosophies in total knee arthroplasty (TKA), aiming to restore native knee biomechanics while respecting individual soft-tissue behaviour. Although recently described as an 'umbrella term', FA has evolved through structured and reproducible workflows supported by image-based robotic technology, enabling three-dimensional planning and dynamic intraoperative assessment. This editorial summarizes the evolution of FA from its original definition to its current interpretation as functional knee positioning, emphasizing its dynamic and three-dimensional nature. Key aspects, including workflow principles, sagittal and coronal alignment during flexion, application in valgus knees, management of the anterior compartment ('third space'), and the influence of implant- and patient-related factors, are discussed. Current clinical evidence supports FA as a safe and effective strategy across different knee phenotypes, highlighting the importance of individualized alignment targets rather than fixed coronal goals. By contextualizing recent biomechanical and clinical data, this editorial aims to clarify fundamental concepts and promote consistent application and reporting of FA in contemporary TKA.