Table 1.

Histopathological Scoring Criteria

Score	Inflammation	Bone erosion	Cartilage damage
			Remote from pannus	Adjacent to pannus
0	Normal	Normal	Normal	Normal
1	Minimal infiltration of inflammatory cells and/or mild edema	Small areas of resorption, not readily apparent on low magnification, in trabecular or cortical bone.	Minimal to mild loss of cartilage with no obvious chondrocyte loss or collagen disruption	Pannus formation with superficial cartilage destruction
2	Mild infiltration	More numerous areas of resorption, not readily apparent on low magnification, in trabecular or cortical bone.	Mild loss of cartilage with mild (superficial) chondrocyte loss and/or collagen disruption	Pannus formation with moderate cartilage destruction (depth to the middle zone)
3	Moderate infiltration	Obvious resorption of trabecular and cortical bone, without full thickness defects in the cortex; loss of some trabeculae; lesions apparent on low magnification.	Moderate loss of cartilage with moderate multifocal (depth to middle zone) chondrocyte loss and/or collagen disruption	Pannus formation with marked cartilage destruction (depth to the tidemark)
4	Marked infiltration	Full thickness defects in the cortical bone and marked trabecular bone loss, without distortion of the profile of the remaining cortical surface.	Marked loss of cartilage with marked multifocal (depth to deep zone) chondrocyte loss and/or collagen disruption	N/A
5	Severe infiltration	Full thickness defects in the cortical bone and marked trabecular bone loss, with distortion of the profile of the remaining cortical surface.	Severe diffuse loss of cartilage with severe multifocal (depth to tidemark) chondrocyte loss and/or collagen disruption	N/A

Histopathological criteria was modified from a previously described method. 41

Abbreviation: N/A, not applicable.