TABLE II.

MRI Scoring System for Subchondral Bone^*

	Points
Subchondral bone density: abnormal signal intensity in the subchondral bone deep to the defect indicating a loss in density
0% (none)	0
1%-25% (slight)	1
26%-50% (mild)	2
51%-75% (moderate)	3
76%-100% (severe)	4
Subchondral bone fluid/edema; distribution and size of affected area also considered
0% (none)	0
1%-25% (slight)	1
26%-50% (mild)	2
51%-75% (moderate)	3
76%-100%—include cystic change (severe)	4
Trabecular bone sclerosis as compared with the normal signal pattern for trabecular bone versus subchondral bone (guide for dense bone with no fat); distribution and size of affected area also considered
0% (none)	0
1%-25% (slight)	1
26%-50% (mild)	2
51%-75% (moderate)	3
76%-100% (severe)	4
Trabecular bone edema as compared with the signal intensity of synovial fluid representing the fluid content in the bone; distribution and size of affected area also considered
0% (none)	0
1%-25% (slight)	1
26%-50% (mild)	2
51%-75% (moderate)	3
76%-100% (severe)	4
Subchondral bone overgrowth as proportion of defect depth; area affected also considered
0% (none)	0
1%-25% (slight)	1
26%-50% (mild)	2
51%-75% (moderate)	3
76%-100% (marked)	4

^*The maximum possible score is 20 points, and a lower score is better.