Phlebographic findings in venous thrombosis following total hip replacement.

The specific appearance of venous thrombosis following total hip replacement was analysed by reviewing 45 positive phlebograms from 122 patients participating in a concurrent trial against thromboembolism. Almost all thrombi were asymptomatic and non-occlusive. Forty-four per cent of the thrombi were exclusively confined to the calf. The muscular veins were the most common location, followed by the fibular and posterior tibial veins. Ipsilateral thrombi predominated over thrombi in the non-operated leg. Thirty-six per cent were located in the ipsilateral thigh and the major part was found in the proximal part of the femoral veins. Nearly all were related to valve cusps, free-floating and were of small size. In 20 per cent, thrombi were found in both the calf and the thigh. Neither contralateral thigh thrombi, nor pelvic thrombi were found. Of 25 patients with pulmonary embolism, all but 3 asymptomatic, 64 per cent had thigh thrombi. A multifocal location of thrombi was present but two major types of thrombosis were distinguished; calf vein thrombosis probably due to venous stasis and femoral thrombosis caused by the local surgical trauma.