What should be considered in using standard knee radiographs to estimate mechanical alignment of the knee?
OBJECTIVE: Anatomical tibiofemoral angle (anatomical TFA) of the knee measured on standard knee radiographs is still widely used as proxy for mechanical tibiofemoral angle (mechanical TFA), because of the practical and economic limitations in using full-limb radiographs. However, reported differences between anatomical and mechanical TFAs show wide variations. The first aim of this study was to determine whether gender, the presence of advanced osteoarthritis (OA), and history of total knee arthroplasty (TKA) influence the differences between anatomical and mechanical TFAs. The second aim was to identify anatomical features that cause divergences between anatomical and mechanical TFAs, and the final aim was to determine whether anatomical TFA measured using reference points more distant from the knee provides more accurate estimates of mechanical TFA. DESIGN: In 102 knees with advanced OA before and after TKAs and 99 control knees with no/minimal OA, we assessed the differences between
