| a. Overall defect evaluation (include entire defect) |
Points |
| 1. Percent filling with neo-formed tissue |
75–100% |
3 |
| 50–75% |
2 |
| 25–50% |
1 |
| 0–25% |
0 |
| b. Subchondral bone evaluation |
Points |
| 2. Percent filling with neo-formed tissue in subchondral bone |
75–100% |
3 |
| 50–75% |
2 |
| 25–50% |
1 |
| 0–25% |
0 |
| 3. Subchondral bone morphology |
Normal, trabecular bone |
4 |
| Trabecular, with some compact bone |
3 |
| Compact bone |
2 |
| Compact bone and fibrous tissue |
1 |
| Only fibrous tissue or no tissue |
0 |
| 4. Extent of neo-tissue bonding with adjacent bone in the subchondral 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 |
Points |
| 5. Morphology of neo-formed surface tissue |
Mainly hyaline cartilage |
6 |
| Fibrocartilage (spherical cell morphology >75% of cells) |
4 |
| Only fibrous tissue (spherical cell morphology <75% of cells) |
2 |
| No tissue |
0 |
| 6. Thickness of neo-formed cartilage |
Similar to the surrounding cartilage |
3 |
| Greater than surrounding cartilage |
2 |
| Less than the surrounding cartilage |
1 |
| No cartilage |
0 |
| 7. Joint surface regularity |
Smooth, intact surface |
3 |
| Surface fissures (<25% neo-surface thickness) |
2 |
| Deep fissures (25–99% neo-surface thickness) |
1 |
| Complete disruption of the neo-surface |
0 |
| 8. Chondrocyte clustering |
None |
3 |
| Less than 25% of chondrocytes |
2 |
| 25–100% chondrocytes |
1 |
| No chondrocytes present (no cartilage) |
0 |
| 9. Chondrocyte and GAG content of neo-cartilage |
Normal cellularity with normal Alcian blue staining |
3 |
| Normal cellularity with moderate Alcian blue staining |
2 |
| Obviously fewer cells with poor Alcian blue staining |
1 |
| Few cells with no or little Alcian blue staining or no cartilage |
0 |
| 10. Chondrocyte and GAG content of adjacent cartilage |
Normal cellularity with normal Alcian blue staining |
3 |
| Normal cellularity with moderate Alcian blue staining |
2 |
| Obviously fewer cells with poor Alcian blue staining |
1 |
| Few cells with no or little Alcian blue staining or no cartilage |
0 |
| 11. Cartilage vascularization |
Absent |
1 |
| Present |
0 |
| Maximum possible total score |
34 |
| Percent degradation of the PLGA (if any) |
75–100% |
3 |
| 50–75% |
2 |
| 25–50% |
1 |
| 0–25% |
0 |
