Mechanical alignment has been a fundamental tenet of total knee arthroplasty (TKA) since modern knee replacement surgery was developed in the 1970s. The objective of mechanical alignment was to infer the greatest biomechanical advantage to the implant to prevent early loosening and failure. Over the last 40 years a great deal of innovation in TKA technology has been focusing on how to more accurately achieve mechanical alignment. Recently the concept of mechanical alignment has been challenged, and other alignment philosophies are being explored with the intention of trying to improve patient outcomes following TKA.

This article examines the evolution of the mechanical alignment concept and whether there are any viable alternatives.

Chris Lavy is an orthopaedic surgeon in Oxford (UK) who lived and worked in Malawi for ten years. There he helped build an orthopaedic hospital and research unit. He was also one of the founders of COSECSA, the regional college of surgeons for East and Central Africa in 1999.