Table 2.

Modified O`Driscoll histological score.

Characteristic	Grading	Score
I. Nature of predominant tissue	Hyaline cartilage	4
	Mostly hyaline cartilage	3
	Mixed hyaline and fibrocartilage	2
	Mostly fibrocartilage	1
	Some fibrocartilage, mostly nonchnodrocytic cells	0
II. Structural characteristics
A. Surface irregularity	Smooth and intact	3
	Superficial horizontal lamination	2
	Fissures	1
	Severe disruption, including fibrillation	0
B. Structural integrity, homogeneity	Normal	2
	Slight disruption, including cysts	1
	Severe disintegration, disruptions	0
C. Thickness	100% of normal adjacent cartilage	2
	50–100% or thicker than normal	1
	0–50% of normal cartilage	0
D. Bonding to adjacent cartilage	Bonded at both ends of graft	2
	Bonded at one end or partially both ends	1
	Not bonded	0
III. Freedom from cellular changes of degeneration
A. Hypocellularity	Normal cellularity	2
	Slight hypocellularity	1
	Moderate hypocellularity, or hypercellularity	0
B. Chondrocyte clustering	No clusters	2
	<25% of the cells	1
	25–100% of the cells	0
IV. Freedom from degenerate changes in adjacent cartilage	Normal cellularity, no clusters, normal staining	3
	Normal cellularity, mild clusters, moderate staining	2
	Mild or moderate hypo/hypercellularity, slight staining	1
	Severe hypocellularity, poor or no staining	0
V. Subchondral bone
A. Reconstruction of subchondral bone	Normal	3
	Reduced subchondral bone reconstruction	2
	Minimal subchondral bone reconstruction	1
	No subchondral bone reconstruction	0
B. Inflammatory response in subchondral bone region	None/mild	2
	Moderate	1
	Severe	0
VI. Safranin O staining	Normal or near normal	3
	Moderate	2
	Slight	1
	None	0
Total, max		28