Structural and surface properties of human articular cartilage from the LFC and MFC. Cartilage thickness (a), mean (b) and variance (c) of the reflectance score assessed after India ink staining, overall histopathological index of cartilage degeneration (d) and surface irregularity assessed by histopathological grading (e) from age-matched donors of cartilage with articular surfaces that were macroscopically normal (NLA), mildly fibrillated (DGN), and mildly fibrillated from joints undergoing total knee replacement (OA). *p<0.05, **p<0.01, ***p<0.005 versus NLA samples.