[Arthrocele of the knee joint--a differential diagnosis to deep venous thrombosis].

The symptoms of a thrombosis in deep veins of the calf in patients with rheumatoid arthritis should have thought of the possibility of a synovial cyst or synovial cyst rupture. Because of their too small specificity clinical findings do not allow to decide for one of the two diagnosis. Phlebography and/or arthrography effect the clarification which is necessary for an effective therapy with low risk. Arthrosonography gets increasing importance instead of arthrography.