Figure 2.

A: grade 1 osteoarthritic lesions had minor roughening of the articular-epiphyseal cartilage complex (AECC) and did not penetrate deeper than 2 mm (caput, femur). B: grade 2 lesions were moderate and penetrated 2-3 mm into the AECC (lateral trochlea, humerus). C: grade 3 lesions were severe and penetrated over 3 mm into the AECC (lateral condyle, tibia). D: grade 4 lesions were osteochondrosis dissecans-like lesions (lateral trochlea, femur).