Fig. 3
Definition of the orientation of the patellar FHA. a With respect to the angles between the patellar FHA and the coronal plane (AF-C), it was set positive when the FHA was located from posteromedial to anterolateral (line α) and negative when the FHA was located from posterolateral to anteromedial (line β). b With respect to the angles between the FHA and the level plane (AF-L), it was set positive when the FHA was located from superolateral to inferomedial (line γ) and negative when the FHA was located from superomedial to inferolateral (line δ)