Joint cartilage is a dynamic tissue that reacts to trauma, inflammation, an
d other insults by attempting to repair its matrix. This reaction results i
n the release of cartilage macromolecules into the body fluids. analysis of
these fluids has identified a limited number of at least somewhat tissue-s
pecific markers of altered cartilage metabolism. Analyses of serum are less
specific and less sensitive than analyses of synovial fluid, but their use
as research tools in clinical studies, drug development, and experimental
work in animal models is increasing.