We performed preoperative and postoperative duplex ultrasonography examinations on both lower extremities in 128 patients undergoing 146 hip and knee reconstructive procedures. The results of the examinations were reviewed by an independent radiologist who specializes in these studies. Three of the 128 patients (146 procedures; 2.1%) had evidence of a deep venous thrombosis or other venous abnormality before surgery. Three additional patients developed a deep venous thrombosis after surgery, despite mechanical and pharmacologic prophylaxis. We have discontinued performing preoperative duplex ultrasonography prior to primary, uncomplicated total joint replacement of the lower extremities. We continue to perform duplex ultrasonography before surgery in patients at high risk, with a history of deep venous thrombosis or phlebitic syndrome, and in those who have previously had major surgery on the lower extremities.