Sector grid. AT adductor tubercle (white dotted line), I row 1, II row 2, III row 3, M medial column, L lateral column, Red dot osteotomy hinge, Green dashed lines posterior part of the medial and lateral femoral condyle, Red circle inflection point, defined as the point at which the distance between the medial cortical bone and Line 4 reaches 2 mm; Line 5, tangential to the lateral facet of the medial femoral condyle; Line 4, tangential to the medial femoral cortical bone; Line 3, tangential to the apices of the posterior part of the medial and lateral femoral condyle; Line 2, parallel to Line 3 and crossing the proximal border of the AT; Line 1, parallel to Line 3 and crossing the inflection point