Studies of a popliteal synovial fistula.

hands. Rheumatoid arthritis was diagnosed and she was treated with phenylbutazone, indomethacin suppositories, and gold injections. A tense swelling developed behind the right knee 6 months later. She was referred to a general surgeon and an initial diagnosis of fibrosarcoma was made. However, at operation, a synovial popliteal cyst was found and removed. After this, synovial fluid began to leak from the lower end of the wound and during the next 2 months a fistulous track developed (Fig. 1).