Jerry Tenenbaum, MD, FRCPC
Mount Sinai Hospital and
Baycrest Centre for Geriatric Care,
University of Toronto,
Osteoarthritis (OA) is a chronic disease of the joint that results in degeneration of the cartilage and bone. However, in osteoarthritis, it is not uncommon to see intermittent or even chronic evidence of inflammation in the affected joint. Patients may experience stiffness after immobility (in the morning or after sitting for a long time), warmth and erythema of the joint, and soft tissue swelling and/or synovial effusion. On history taking and physical exam, these findings attest to the inflammatory nature of the involved osteoarthritic joint at the time. A microscopic examination of the synovium of patients with osteoarthritis will often show the presence of inflammation. Though cartilage and bone seem to be the primary targets of damage, it is likely that inflammation within the synovium may play an important role in the progressive damage to these joint tissues. Primary involvement of synovium may occur in some patients and secondary synovitis is commonly seen. This is associated with the intermittent or chronic presence of crystals (calcium pyrophosphate dihydrate, hydroxyapatite) or synovitis associated with stimulation by joint damage debris.