Figure 1.

Osteochondritis dissecans (OCD) localization modified according to Cahill and Berg (1983).¹¹ In the anteroposterior diagram, the anatomic zones 1 to 5 are used. They are delineated by bisecting the individual condyles. Zone 3 is outlined by the walls of the intercondylar tunnel. In the lateral diagram, zone A is limited by a line projected along the roof of the intercondylar tunnel. Zones B and C are separated by a line projecting distally from and parallel to the posterior femoral cortex.