TABLE 2.

ICRS histological grading system

Item	Description
Ti	1: Exclusively noncartilage
	2: Mostly noncartilage
	3: Mostly fibrocartilage
	4: Mostly hyaline cartilage
Matx	1: None
	2: Slight
	3: Moderate
	4: Strong
Stru	1: Severe disintegration
	2: Cysts or disruptions
	3: No organization of chondrocytes
	4: Beginning of columnar organization of chondrocytes
	5: Normal, similar to healthy mature cartilage
Clus	1: 25–100% of the cells clustered
	2: <25% of the cells clustered
	3: No clusters
Tide	1: <25% of the calcified cartilage layer intact
	2: 25–49% of the calcified cartilage layer intact
	3: 50–75% of the calcified cartilage layer intact
	4: 76–90% of the calcified cartilage layer intact
	5: Complete intactness of the calcified cartilage layer
Bform	1: No formation
	2: Slight
	3: Strong
SurfH	1: Severe fibrillation or disruption
	2: Moderate fibrillation or irregularity
	3: Slight fibrillation or irregularity
	4: Normal
FilH	1: <25%
	2: 26–50%
	3: 51–75%
	4: 76–90%
	5: 91–110%
Latl	1: Not bonded
	2: Bonded at one end/partially both ends
	3: Bonded at both sides
Basl	1: <50%
	2: 50–70%
	3: 70–90%
	4: 91–100%
InfH	1: Strong inflammation
	3: Slight inflammation
	5: No inflammation
Hgtot	45 points

Note: This system evaluates repaired tissue based on 11 items: Ti: tissue morphology; Matx: matrix staining; Stru: structural integrity; Clus: cluster formation; Tide: tidemark opening; Bform: bone formation; SurfH: histological appraisal of surface architecture; FilH: histological appraisal of the degree of defect filling; Latl: lateral integration of defect‐filling tissue; Basl: basal integration of defect‐filling tissue; InfH: histological signs of inflammation. The total score (Hgtot) range is 11–45. ICRS: International Cartilage Regeneration and Joint Preservation Society.