Fig. 1

A Anterior view of the distal femur. Superimposed are the proximal (P) and the distal (D) schematic measurement planes used to virtually osteotomize the femur. The proximal plane is defined by the axial MR image, when the trochlea is initially completely covered with cartilage. The distal plane is defined by the axial MR image before the trochlear groove curves into the femoral notch. The wedge containing the osteotomized bone is depicted in red. B Schematic axial slice of the distal femur showing the virtual osteotomy conducted. The sulcus (S) is lateralized (L) and deepened (D) according to the reported results by Fucentese et al. [16], oriented parallel and perpendicular to the baseline (BL) respectively. The bone anterior to the line (depicted in red) connecting the most prominent lateral condylar point (LC), the newly defined sulcus (S1) and the most prominent medial condylar point (MC) is osteotomized