Figure 5.

Schematics and outcomes of OARSI grading. (A-E): Schematics of OARSI Grades 0 to 4. Grade 0: the surface is intact and smooth. Matrix and chondrocytes are well organized. Grade 1: intact but uneven surface demonstrated by fibrillation. Cell death or proliferation may be accompanied. Grade 1.0: cell intact; Grade 1.5: cell death. Grade 2: surface interrupted. Fibrillation extends deeper. Cell death, proliferation and hypertrophy may be accompanied. Grade 2.0: fibrillation through the superficial zone; Grade 2.5: surface abrasion with matrix loss within the superficial zone. Grade 3: vertical fissures extend to the middle zone. Fibrillation extends to the middle zone. Cell death and proliferation may be accompanied mainly adjacent to fissures. Grade 3.0: simple fissures; Grade 3.5: branched or complex fissures. Grade 4: cartilage erosion. Cartilage matrix loss and cyst formation within the cartilage matrix. Grade 4.0: superficial zone delamination; Grade 4.5: mid-zone excavation. ⁸ (F): The outcomes of OARSI grading. The results are presented as the mean ± standard deviation. **, P < 0.01; ****, P < 0.0001.