Roentgenographic Analysis of Patellofemoral Congruence
Alan Merchant, Richard Mercer, Richard Jacobsen, Charles Cool
JBJS 1974
Merchant View - patient is supine on the x-ray table. The knees are flexed 45 degrees and the legs are strapped. The beam to femur angle is 30 degrees and the plate is positioned against the shins.
Sulcus Angle of Brattstrom - angle formed by the highest points on the medial and lateral femoral condyles and the lowest point of the sulcus
Congruence Angle - sulcus angle is bisected to establish the reference line. Another line is drawn from the apex of the sulcus to the lowest point on the patellar articular surface.