Interobserver Analysis of Standard Foot and Ankle Radiographic Angles

Standard foot and ankle radiographs have long been studied and averages formulated in an attempt to provide a common framework for understanding the relationships of the foot and ankle, not only for surgical planning but also to determine normal versus abnormal relationships. The authors describe 8 angles measured on 100 patients by up to 18 observers (4 attending physicians, 12 residents, and 2 students). This study validates the previously documented normal angles using a significantly larger observer group as well as a greater number of analyzed angles. Additionally, this study reveals the tibio-second metatarsal angle on the calcaneal axial view is not a reliable radiographic angle for evaluation of foot and ankle deformity. Intraclass correlation coefficients were also analyzed, which displayed variability in measurements based on level of training, with residents being the most accurate, followed by attending physicians and then students. Foot and ankle radiographs are essential for surgical planning, and understanding normal versus abnormal is key before any surgical planning can be accurately performed.