Table 1 OARSI histological assessments of osteoarthritis.
Grade | Osteoarthritic damage |
|---|---|
0 | Normal |
0.5 | Loss of Safranin-O without structural changes |
1 | Small fibrillations without loss of cartilage |
2 | Vertical clefts down to the layer immediately below the superficial layer and some loss of surface lamina |
3 | Verical clefts/erosion to the calcified cartilage extending to < 25% of the articular surface |
4 | Vertical clefts/erosion to the calcified cartilage extending to 25–50% of the articular surface |
5 | Vertical clefts/erosion to the calcified cartilage extending to 50–75% of the articular surface |
6 | Vertical clefts/erosion to the calcified cartilage extending > 75% of the articular surface |
