The language of knee alignment updated definitions and considerations for reporting outcomes in total knee arthroplasty

Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (tKA), not only with the latest technologies and prostheses, but also fundamental decisions on alignment philosophies. From 'mechanical' to 'adjusted mechanical' to 'restricted kinematic' to 'unrestricted kinematic' - and how constitutional alignment relates to these - there is potential for ambiguity when thinking about and discussing such concepts. this annotation summarizes the various alignment strategies currently employed in tKA. it provides a clear framework and consistent language that will assist surgeons to compare confidently and contrast the concepts, while also discussing the latest opinions about alignment in tKA. Finally, it provides suggestions for applying consistent nomenclature to future research, especially as we explore the implications of 3D alignment patterns on patient outcomes.