The Changing Depth Dependant Properties of Articular Cartilage During Postnatal Development

During skeletal development and maturation compositional and architectural changes occur in articular cartilage. Specifically, the collagen architecture changes from a predominantly isotropic structure in immature articular cartilage to a mature arcade-like zonal structure first described by Benninghoff (1925)^1,2,3. The goal of this study was to elucidate how the structure and composition of articular cartilage change during postnatal development and maturation and to relate this to the mechanical properties of the tissue, focusing in particular on how the key superficial region of the tissue adapts with age. To this end articular cartilage from a variety of age groups (one month old-immature, one year old-skeletally mature and three years old-fully mature) were subjected to increasing levels of strain. Local levels of deformation in the tissue were determined by fluorescently labelling and imaging cells that acted as fiducial markers. This enabled the local levels of strain and hence tissue mechanical properties to be determined with age and skeletal maturity.