Type II collagen is composed of a triple helix of three identical α chains. These molecules associate to form a fibril that is stabilized by intermolecular crosslinks1. Damage to the fibrillar meshwork, made up of primarily type II collagen (z 90–95%), ma

Type II collagen and aggrecan (a large, aggregating proteoglycan) are the two major components of the extracellular matrix of cartilage. The collagen, which is present in a fibrillar form, provides tensile strength whereas the aggrecan is responsible for compressive stiffness of cartilage3-5. Early damage to type II collagen is predominantly pericellular/ territorial suggests that in the majority of cases collagen damage was mediated by the chondrocyte.