Fig. 2

Three-dimensional angles of the knee joint, the talocrural joint and the subtalar joint were defined. As the knee joint angle increased/decreased, the sagittal, coronal, and horizontal planes were defined as extension/flexion, varus/valgus, and tibial internal/external rotation; the talocrural joint angle was defined as dorsiflexion/plantarflexion, inversion/eversion, and internal/external rotation; and the subtalar joint angle was defined as dorsiflexion/ plantarflexion, inversion/eversion, and internal/external rotation