Nineteen knees in eighteen cases of osteochondral fracture that operative findings were recorded in detail on were studied with respect to patellar cartilage lesions around the osteochondral defect. On the abnormal articular surface, the incidence of each type of lesion observed was as follows: fissure, 12 knees; softening, 13 knees; fibrillation, 5 knees; ulcer, 1 knee; and repair-like changes, 8 knees. Most of the fissures were deep enough to reach the subchondral bone and ran in the longitudinal direction in the superolateral portion near the osteochondral defect. This could be thought to result from the shearing force passing from the medial to the lateral side of the patella. These articular lesions may be one part of post-traumatic chondropathy like post-traumatic chondromalacia patellae and fracture of the patella are, but they were not progressive, unlike post-traumatic chondromalacia patellae, and were almost painless, unlike fracture of the patella.