Fig. 1.

(A) Posterior condylar angle: the angle between the posterior condylar line and the transepicondylar line. (B) Trochlear angle: the angle between the posterior condylar line and a tangential line passing through the anterior aspects of the medial and lateral trochlea. (C) Lateral trochlear inclination: the angle between the posterior condylar line and the lateral trochlear facet. (D) Medial trochlear inclination: the angle the posterior condylar line and the medial trochlear facet. (E) Sulcus angle: the angle between the medial and lateral trochlear facets. (F) Trochlear depth: the inset depth of the trochlear groove relative to the mean of the medial and lateral femoral condyle outsets calculated as [(a−b)+(b−c)]/2. a: lateral facet height, b: medial facet height, c: perpendicular line from the sulcus to the posterior condylar line.