Synovitis

Synovitis is inflammation of the synovial membrane, the thin lining inside a joint that produces lubricating fluid. The joint becomes swollen, warm, tender and painful to move, and may feel stiff. It occurs in rheumatoid arthritis, gout, infection, injury and sometimes osteoarthritis. Doctors confirm it by examination, ultrasound or MRI, and sometimes by testing fluid drawn from the joint.