RHEUMATOID-ARTHRITIS OF THE KNEE - RADIOL OGICAL EVALUATION

Rheumatoid arthritis is a chronic, multisystemic disease. The characte ristic feature is persistent inflammatory synovitis. The knee joint is commonly involved with synovial hypertrophy, chronic effusion, and fr equently ligamentous laxity. Pain and swelling behind the knee may be caused by extension of inflamed synovium into the popliteal space (Bak er's cyst). Plain radiographs of the knee joint remain the basic radio logical procedure, although early in the disease they might not provid e significant changes. Sonography sufficiently reveals synovial fluid and Baker cysts, but cannot be recommended fur evaluation of synovial proliferations or pannus formation. Computer tomography has only limit ed indications and may be used for the evaluation of subtle erosive le sions or the quantitation of osteoporotic changes. Magnetic resonance imaging has shown excellent visualization of cartilage, fluid, synoviu m and soft tissues and is the method of choice for the demonstration o f early affection and the evaluation of pannus activity and therapy co ntrol, With daministration of contrast agents (gadolinium), dynamic st udies may demonstrate inflammatory activity. Modern MR sequences, such as T1 SE ''fat sat'' or magnetization transfer, further improve the d iscrimination of cartilage, pannus and synovial fluid.