Table 1.
Histological Scoring System
| Scoring categories | Score |
|---|---|
| 1. Intensity of Safranin O-fast green stain36 | |
| No stain | 0 |
| Weak staining of poorly formed matrix | 1 |
| Moderately even staining | 2 |
| Even dark stain | 3 |
| 2. Distance between cells/amount of matrix accumulated36 | |
| High cell density with no matrix in between (no spacing between cells) | 0 |
| High cell density with little matrix in between (cells <1 cell-size apart) | 1 |
| Moderate cell density with matrix (cells ∼1 cell-size apart) | 2 |
| Low cell density (cells >1 cell-size apart) with an extensive matrix | 3 |
| 3. Cell morphologies36 | |
| Condensed/necrotic/pyknotic bodies | 0 |
| Spindle/fibrous | 1 |
| Mixed spindle/fibrous with rounded chondrogenic morphology | 2 |
| Majority of rounded/chondrogenic | 3 |
| 4. Uniformity of Safranin O staining37 | |
| Complete disorganization of stained areas | 0 |
| Less than 50% of Safranin O stained areas with regard to the total volume | 1 |
| 50%–80% of Safranin O stained areas with regard to the total volume of the section | 2 |
| Overall homogeneity of the staining | 3 |
| 5. Abnormal calcifications within the cartilage newly formed37 | |
| Strong presence of abnormal calcifications inside the neo-formed cartilage | 0 |
| Presence of some calcification spots inside the newly formed cartilage | 1 |
| Presence of very few calcification spots inside the repaired cartilage | 2 |
| Complete absence of calcifications throughout the newly formed cartilage | 3 |
| 6. Vessels ingrowth (within the newly formed tissue)37 | |
| Vessels ingrowth inside the core of the repaired cartilage | 0 |
| Vessels ingrowth until the inner rim of the neo-formed cartilage (approximately two thirds of newly formed cartilage's total volume) | 1 |
| Vessels ingrowth until the outer rim of the neo-formed cartilage (approximately one third of newly formed cartilage's total volume) | 2 |
| No presence of vessels or vessels confined in the external fibrotic capsule | 3 |
| 7. Final score | |
| Not-formed cartilage. Basically, just fibrotic tissue | 0–6 |
| Inhomogeneous and fibrocartilagineous tissue, having just a few and nonconnected areas of a good newly formed cartilage | 6.1–11 |
| Moderately good tissue, having less than 60%—with regard to the total volume—of a good newly formed cartilage | 11.1–15 |
| Very good quality of homogeneity of newly formed cartilage | 15.1–18 |