Emerging knowledge of cartilage metabolism and structure has stimulated efforts to develop new cartilage-monitoring techniques in health and disease. This article gives an overview of cartilage matrix structure, cartilage metabolism, and significant exogenous factors to show how such knowledge can guide the development of new means to monitor cartilage.Delayed contrast enhanced MRI of cartilage (dGEMRIC) and analysis of molecular biomarkers of joint cartilage metabolism in body fluids are two such methods that have made it possible to examine cartilage matrix structure and to study metabolic processesin vivo.