Fig. 5

Grade (c) lesion in MRI evaluation and arthroscopic observation. A: the depth of the cartilage lesion was greater than 1/2 of the thickness of the cartilage, but there was no full-thickness lesion of the cartilage, and the subchondral bone was not exposed, was recorded as (c). B: cartilage lesion was found greater than 1/2 of the thickness of the cartilage, subchondral bone was not exposed