Identification of α₂‐Macroglobulin as a Master Inhibitor of Cartilage‐Degrading Factors That Attenuates the Progression of Posttraumatic Osteoarthritis

The plasma protease inhibitor α2 M is not present in sufficient concentrations to inactivate the high concentrations of catabolic factors found in OA SF. Our findings suggest that supplemental intraarticular α2 M provides chondral protection in posttraumatic OA.