Table 1.

Classification of knee cartilage defects according to ICRS (International Cartilage Repair Society Classification).

Score		Clinical Description
0		Normal cartilage
1	a	Soft indentation
	b	Superficial fissures and cracks
2		Lesions extending down to less than 50% of the cartilage depth
3	a	Defects extending down to more than 50% of the cartilage layer
	b	Defects extending down to the calcified layer
	c	Defects extending down to but not through the defects extending down to subchondral bone layer
	d	Delamination, including bulging of the cartilage around the lesion
4	a	Penetration of the subchondral bone but not across the entire diameter of the defect
	b	Penetration of the subchondral bone across the full diameter of the defect