To the Editor.
—Francis et al1 suggest that warfarin therapy is more effective than external pneumatic compression in preventing proximal vein thrombosis after hip replacement surgery, but that it is less effective for the prevention of calf thrombosis. They advocate routine use of warfarin prophylaxis and suggest routine venography prior to discharge or extended use of warfarin to protect those patients who develop isolated calfthrombosis. However, orthopedic surgeons are reluctant to use perioperative anticoagulants.2 Given this reluctance, alternative strategies might be developed based on the results of the study by Francis et al. One such alternative strategy would be the use of external pneumatic compression and postoperative surveillance with duplex ultrasound. Duplex ultrasound is highly sensitive and specific for asymptomatic proximal venous thrombosis following hip surgery.3,4 Duplex ultrasound does not reliably detect isolated calf thrombosis, but serial ultrasound examinations have been used in other settings to detect
Bauer DC. Ultrasound Surveillance to Detect Postoperative Venous Thrombosis. JAMA. 1992;268(19):2650. doi:10.1001/jama.1992.03490190050022