Fig. 3

Measurements on the transverse image obtained 3 cm above the femorotibial joint space. (A) The angle of trochlear facet. The SA was the angle between the ab and ac; LTA and MTA were the angle between the posterior condyle line (PCL) and the ab and ac respectively. a: the deepest point of the trochlear sulcus; b and c: the point of the most prominent point of the lateral and medial femoral condyle. (B) The parameters of trochlear morphology. LFL was the distance between a and b. MFL was the distance between a and c. TD was the distance between b and c. TH, LTH and MTH were the vertical distance from a, b and c to PCL. Note: LFL lateral facet length, LTA lateral trochlea inclination angle, LTH lateral trochlear height, MFL medial facet length, MPFL medial patellofemoral ligament, MTA medial trochlear inclination angle, MTH medial trochlear height. PCL posterior condyle line, TD lateral-medial trochlear facet distance, TH trochlea sulcus height, SA sulcus angle