One hundred fifty-seven patients who underwent hip replacement surgery were studied by the 125I-fibrinogen leg scan technique. This method sensitively detects silent venous thrombosis and very small thrombi. By comparison with phlebograms, the isotope technique is somewhat oversensitive in that 26% of 46 phlebograms (12) showed no thrombi, but specificity was good in that on the basis of six other phlebograms, obtained because of persistent physical findings, the isotope leg scan was never "falsely normal." A two-phase drug trial failed to demonstrate an alternative treatment significantly better than warfarin sodium, but did indicate that wound hematoma occurring in patients given heparin sodium subcutaneously in the dosage used constitutes a real drawback for this therapy after orthopedic surgery.
Hume M, Kuriakose TX, Zuch L, Turner RH. 125I Fibrinogen and the Prevention of Venous Thrombosis. Arch Surg. 1973;107(5):803-806. doi:10.1001/archsurg.1973.01350230155028