Table 1.

Classification and grading of chondral lesions

Outerbridge
Grading	Depth	Size
0	Normal
1	Softening and swelling of cartilage
2	Partial thickness, < 50% of cartilage thickness	< 1.25 cm diameter
3	Partial thickness, > 50% of cartilage thickness	> 1.25 cm diameter
4	Full thickness down to subchondral bone	Any

ICRS cartilage injury classification
Grade	Naming and description
0	Normal
1	Nearly normal: superficial indentations/fissures
2	Abnormal: lesions extending < 50% of cartilage thickness
3	Severely abnormal: lesions extending > 50% of cartilage thickness and up to but not through the subchondral bone
4	Severely abnormal: lesions extending through the subchondral bone

Modified from Dallich et al. [36]