Modified Bonar scale for grading of vascularity in tendinosis
| Grade | 0 | 1 | 2 | 3 |
|---|---|---|---|---|
| Vascularity | Inconspicuous blood vessels coursing transversely in between bundles | Occasional conspicuous capillaries; less than 1 per ‘10 high power fields’ | One to two conspicuous capillaries per ‘10 high power fields’; occurrence of irregular vascular structures | Greater than two conspicuous capillaries per ‘10 high power fields’; presence of highly irregular vascular structures |
Modified Bonar scale for grading of vascularity in rabbit tendinosis. A 40×/0.75 microscope objective was used for the examination. As in the original Bonar scale26 a score of 0–3 was applied (also used in previous studies27 28), and the grades were defined as follows: 0, normal pattern of vascularity; 1, slightly abnormal; 2, (moderately) abnormal; 3, markedly abnormal vascular pattern. Focus was given to the occurrence of vessels/capillaries running longitudinally in the tendons (figure 2C), that is, in parallel to the collagen bundles, as these vessels have been seen to be increased in number in conditions of tendon degeneration.27 In contrast, the occurrence of vessels coursing transversely between bundles (figures 2C and 3A) was considered a normal finding. However, the occurrence of a very high number of visible, transversely oriented vascular branches was considered not normal and included in the term ‘irregular vascular structures’, which also refers to irregular shapes of vessels. Therefore, in summary, an increased number of longitudinally running vessels, unusually high amounts of transversely oriented vessels and the occurrence of abnormal vascular structures gave gradually increasing scores.