Free radicals in primary knee osteoarthritis.

Free radicals have an important role in the pathogenesis of knee osteoarthritis. Reactive oxygen species (ROS) produced by abnormal chondrocyte metabolism exceeds the physiological buffering capacity and results in oxidative stress. The excessive production of ROS can damage proteins, lipids, nucleic acids, and matrix components. They also serve as important intracellular signaling molecules that amplify the inflammatory response. An understanding of oxidative stress involved in this disease might allow the use of antioxidant therapies in the prevention and/or treatment of knee osteoarthritis.