TABLE 2.

Modified Mankin Grading Scale Used to Assess Histological Staining of the Tibial Articular Cartilage

Measure	Score
	0	1	2	3	4	5	6
Glycosaminoglycan staining	Uniform	Loss of staining in superficial zone <50% of length of plateau	Loss of staining in superficial zone >50% of length of plateau	Loss of staining in upper 2/3 <50% of length of plateau	Loss of staining in upper 2/3 >50% of length of plateau	Loss of staining in full depth of cartilage <50% of length of plateau	Loss of staining in full depth of cartilage >50% of length of plateau
Fissures	Absent	Surface fibrillation <50% of length of plateau	Surface fibrillation >50% of length of plateau	1-2 midzone fissures	3-5 midzone fissures	Full depth fissures or 5+ midzone fissures	Large segments of cartilage eroded with full depth fissures
Tidemark integrity	Normal	Disrupted