The Pathobiology of Osteoarthritis

This article summarizes the current understanding of the pathophysiology of knee osteoarthritis (OA). OA is a common disease of diarthrodial joints with marked prevalence in aging individuals. It is a complex, heterogeneous, whole-joint disease with multiple etiologies. Although articular cartilage degeneration is a hallmark end-stage finding of OA, not all individuals with cartilage damage develop OA. The exact trigger of OA remains to be unequivocally identified, although a number of variable secondary components including age, obesity, and inflammation determine the extent of disease progression. OA bears a strong hereditary component. However, its different genetic etiologies are not equally shared in the diverse human population. In addition, its variable cLinical features have made the understanding of its pathophysiology a daunting task. Several diagnostic tools are available and many more are under development to diagnose early stage OA. The advent of biomarkers and genetic tools for OA research is very promising for stratifying individuals at higher risk for developing OA.