Several methods have been described for bisecting the first metatarsal shaft on radiographs.28 The method used in this study was in accordance with recommen-dations from the American Orthopaedic Foot and Ankle Society.6 Points marking the width of the metaphyseal/diaphyseal region of the proximal phalanx (0.5-1.0 cm proximal and distal to the articular surface) and first metatarsal (1.0-2.0 cm proximal and distal to the articular surface) were selected, and the software calculated the bisection points and HV angle (FIGURE 2B).