Synovial fluid in the calf

While awareness of synovial rupture of the knee joint confirmed by early arthrography increases, concomitant deep-vein occlusion may be being overlooked. Two cases of this are described, illustrating different mechanisms of venous occlusion by synovial rupture. Early thrombosis occurred in one patient from direct pressure as a result of haematoma following anticoagulant therapy and in another due to presumed external irritation of the vein. Although isolated bursae do not apparently rupture, tendon sheaths occasionally do. An example of lateral popliteal mononeuritis as a result of rupture of a tense peroneal tendon sheath is also given. Synovial rupture is primarily a clinical diagnosis but in selected cases, deep calf venography may be useful rather than arthrography. Almost a century ago, William Morrant Baker published his work on synovial protrusions showing his awareness of the consequences of free fluid in the calf. Some comments are made on his life and work.