Table 1. Criteria and scores for histological assessment of menisci.

The range of possible total scores is 0–18. This total score can be converted to a grade as follows: G1=0–4, G2=5–9, G3=10–14, G4=15–18. Grade 1 represents normal tissue, Grade 2 is mild degeneration, Grade 3 is moderate and Grade 4 is severe degeneration.

I	SURFACE including lamellar layer:
		Score
I–I	FEMORAL SIDE:
	A Smooth	0
	B Slight fibrillation or slightly undulating	1
	C Moderate fibrillation or markedly undulating	2
	D Severe fibrillation or disruption	3
I–II	TIBIAL SIDE:
	A Smooth	0
	B Slight fibrillation or slightly undulating	1
	C Moderate fibrillation or markedly undulating	2
	D Severe fibrillation or disruption	3
I–III	INNER BORDER:
	A Smooth	0
	B Slight fibrillation or slightly undulating	1
	C Moderate fibrillation or markedly undulating	2
	D Severe fibrillation or disruption	3
II	CELLULARITY
	A Normal	0
	B Diffuse hypercellularity	1
	C Diffuse hypo/acellular regions	2
	D Hypocellularity (empty lacuna, pycnotic cells)	3
III	COLLAGEN ORGANIZATION/ALIGNMENT AND FIBER ORGANIZATION
	A Collagen fibers organized, homogenous eosinophilic staining of extracellular matrix	0
	B Collagen fibers organized, diffuse foci of hyaline or mucinous degeneration	1
	C Collagen fibers unorganized, confluent foci or bands of hyaline or mucinous degeneration, fraying	2
	D Collagen fibers unorganized, fibrocartilaginous separation (edema, cystic formation), severe fraying and tears	3
IV	MATRIX STAINING (SAFRANIN O - FAST GREEN)
	A None	0
	B Slight	1
	C Moderate	2
	D Strong	3
Cell clusters:		present +, ++, +++
Calcium deposition:		present +, ++, +++