Mitsuyama H et al. (2007) Calcification of human articular knee cartilage is primarily an effect of aging rather than osteoarthritis. Osteoarthritis Cartilage 15: 559–565

Cartilage calcification is associated with knee osteoarthritis (OA). A study by Mitsuyama et al., however, suggests that calcification is primarily a consequence of aging rather than OA.

A total of 106 knee blocks from 56 donors (31 males; average age 50.3 years, range 12–74) were examined; after the condyles were cut into 7–10 mm slabs, high-resolution images were obtained using a Faxitron radiography system to visualize cartilage calcification. The cartilage surface was also assessed visually for signs of fibrillation or erosion and graded on a 4-point scale, where grade 1 represents normal appearance, and grade 4 is cartilage eroded to the bone. A significant correlation was found between percent cartilage calcification and age; this relationship remained when OA condyles were omitted from the analysis. No relationship was found between calcification and OA; increases in calcification were seen between grade 1 and grade 2 cartilage, but no further increases were observed in grade 3 or 4 condyles.

The authors suggest that calcification is a consequence of age-related changes in cartilage composition (e.g. water and proteoglycan content), and might contribute to the progression of OA.