The articular cartilage that lines the bones in your movable joints (finger, knee, hip, shoulder, etc.) still develops after birth, like the rest of the skeleton. Between birth and maturity, remarkable changes occur in the tissue: in this period it develops the depth-dependent composition and structure that it will need in further life.
Important for the depth-dependent adult structure is the remodelling of the collagen network, which we investigated in sheep. We found that collagen fibrils lie predominantly parallel to the surface of the tissue in newborn animals, and that they form an (depth-dependent) arcade-like structure in mature animals. With computational models, we were able to show that strains increase in collagen fibrils that change orientation, and that the amount of collagen increases where these fibril strains increase. We further showed how postnatal reorientation of collagen contributes to the depth-dependent properties that are important in adult life.
After puberty, articular cartilage can no longer remodel or heal, unlike the bones. The process of postnatal development is therefore an important one: the cartilage that you have at puberty, will have to serve for the remainder of your life.
Title thesis: Postnatal development of articular cartilage