1 Introduction Ar ticular cartilage is a specialised connective tissue with unique biological and mechanical properties which depend on the structural design of the tissue and the interactions between its unique resident cells, the chondrocytes, and the extrac- lular matrix (ECM) that makes up the bulk of the tissue (Buckwalter and Mankin 1998). Chondrocytes (Fig. 1 ) are the architects of the ECM (Muir 1995), building the macromolecular framework of the ECM from three distinct classes of mac- molecules: collagens, proteoglycans, and noncollagenous proteins. Of the collagens present in...