Table 1.

Histological gradation of the articular cartilage and synovial changes.

Cartilage
Severity of cartilage pathology characteristics
Normal volume, smooth surface with all zones intact	0
Surface undulations including fissures in surface/upper zone	1
Fissures to mid zone and/or erosion of surface/upper zone	2
Fissures to deep zone and/or erosion through mid zone	3
Full thickness loss of cartilage	4
Severity of chondrocyte pathology characteristics
Normal	0
Loss of superficial cells or relative increased density with occasional clusters	1
Small clusters (2–4 cells) predominate	2
Large clusters (≥5 cells) predominate	3
Cell loss (necrosis/apoptosis) predominate	4
Tidemark
Intact and distinct	0
Not consistent or distinct (loss and/or duplication)	1
Loss of Tidemark which is crossed by blood vessels	2
Total	10
Synovial membrane
Lining cell characteristics
1–2 layers of cells	0
3–6 layers of cells	1
>6 layers of cells	2
Hyperplasia
No villous hyperplasia	0
Short villi	1
Finger-like hyperplasia	2
Cell infiltration characteristics
No cellular infiltration	0
Mid to moderate inflammatory cell infiltrates including small lymphoid follicles	1
Marked, diffuse inflammatory cell infiltrates including large lymphoid follicles	2
Total	6

Parameters evaluated in the gradation of histological changes in paraffin embedded samples.