Clinical and Pathophysiologic Significance of MRI Identified Bone Marrow Lesions Associated with Knee Osteoarthritis

Knee osteoarthritis (OA) affects the joint beyond just the articular cartilage. Specifically, magnetic resonance imagingidentifiedbone marrow lesions (BML) in the subchondral bone have both clinical and pathophysiological significance.Compared to joint space narrowing on traditional radiographs, the presence of BMLs has been better correlated withseverity of clinical symptoms as well as clinical deterioration. Presence of a BML increases the likelihood for progressionto a total knee arthroplasty by up to nine fold. Histochemical analysis of BMLs has shown increased levels of tumornecrosis factor-alpha, matrix metalloproteinases and substance P, thought to stimulate pain receptors in osteoarthritis.