Table 1.

Modified O’Driscoll Score.

I. Nature of Predominant
Hyaline cartilage	4
Mostly hyaline cartilage	3
Mixed hyaline and fibrocartilage	2
Mostly fibrocartilage	1
Some fibrocartilage, mostly nonchondrocytic cells	0
II. Structural Characteristics
A. Surface regularity
Smooth and intact	3
Superficial horizontal lamination	2
Fissures	1
Severe disruption, including fibrillation	0
B. Structural integrity, homogeneity
Normal	2
Slight disruption	1
Severe disintegration, disruptions	0
C. Thickness
100% of adjacent cartilage	2
50-100% of normal cartilage	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 at 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 degenerative 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
Sever 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 maximum score:	28