Fig. 3

Analyzing the deformity and planning the procedure. 1 Hilgenreiner line, (line through both triradiate cartilages). 2 Interischial line. 3 Hilgenreiner epiphyseal angle (HEA). 4 The fixed angle (16°) that is subtracted from the Hilgenreiner epiphyseal angle (HEA). 5 The actual osteotomy angle (angle of correction); angle 5 = angle 3 − angle 4. 6 The angle between the green lines represents the actual angle of the corrective osteotomy; angle 6 = angle 5. 7 Line bisecting the neck of the femur that is used when planning the upper line of the osteotomy