Table 2.
Histological scoring system for the evaluation of (a) overall tissue, (b) subchondral bone, and (c) cartilage in rabbit osteochondral defects.
| Score | |
|---|---|
| (a) Overall defect evaluation (throughout the entire defect depth) | |
| 1. Percent filling with newly formed tissue | |
| 100% | 3 |
| >50% | 2 |
| <50% | 1 |
| 0% | 0 |
| 2. Percent degradation of the implant | |
| 100% | 3 |
| >50% | 2 |
| <50% | 1 |
| 0% | 0 |
| (b) Subchondral bone evaluation (within the bottom 2 mm of defect) | |
| 3. Percent filling with newly formed tissue | |
| 100% | 3 |
| >50% | 2 |
| <50% | 1 |
| 0% | 0 |
| 4. Subchondral bone morphology | |
| Normal, trabecular bone | 4 |
| Trabecular bone, with some compact bone | 3 |
| Compact bone | 2 |
| Compact bone and fibrous tissue | 1 |
| Only fibrous tissue or no tissue | 0 |
| 5. Extent of new tissue bonding with adjacent bone | |
| Complete on both edges | 3 |
| Complete on one edge | 2 |
| Partial on both edges | 1 |
| Without continuity on either edge | 0 |
| (c) Cartilage evaluation (within the upper 1 mm of defect) | |
| 6. Morphology of newly formed surface tissue | |
| Exclusively articular cartilage | 4 |
| Mainly hyaline cartilage | 3 |
| Fibrocartilage (spherical morphology observed with ≥ 75% of cells) | 2 |
| Only fibrous cartilage (spherical morphology observed with < 75% of cells) | 1 |
| No tissue | 0 |
| 7. Thickness of newly formed cartilage | |
| Similar to the surrounding cartilage | 3 |
| Greater than the surrounding cartilage | 2 |
| Less than the surrounding cartilage | 1 |
| No cartilage | 0 |
| 8. Joint surface regularity | |
| Smooth, intact surface | 3 |
| Surface fissures (<25% of new surface thickness) | 2 |
| Deep fissures (≥25% of new surface thickness) | 1 |
| Complete disruption of the new surface | 0 |
| 9. Chondrocyte clustering | |
| None at all | 3 |
| <25% chondrocytes | 2 |
| 25–100% chondrocytes | 1 |
| No chondrocytes present (no cartilage) | 0 |
| 10. Chondrocyte and GAG content of new cartilage | |
| Normal cellularity with normal Safranin O staining | 3 |
| Normal cellularity with moderate Safranin O staining | 2 |
| Clearly less cells with poor Safranin O staining | 1 |
| Few cells with no or little Safranin O staining or no cartilage | 0 |
| 11. Chondrocyte and GAG content of adjacent cartilage | |
| Normal cellularity with normal Safranin O staining | 3 |
| Normal cellularity with moderate Safranin O staining | 2 |
| Clearly less cells with poor Safranin O staining | 1 |
| Few cells with no or little Safranin O staining or no cartilage | 0 |