0 |
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. |
Synovial adherence to margins of cartilage in <3 sites |
2 |
Mild infiltration |
More numerous areas of resorption, not readily apparent on low magnification, in trabecular or cortical bone. |
Synovial adherence to margins of cartilage in 3 or more sites |
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. |
Synovial adherence to cartilage not limited to margins but no full-thickness |
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. |
Full-thickness injury in <3 sites |
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. |
Full-thickness injury in 3 or more sites. |