Thromboembolism Following Total Hip Replacement: A Prospective Investigation of 94 Patients with Emphasis on the Efficacy of Lumbar Epidural Anesthesia in Prophylaxis

Abstract

In a prospective study of 94 otherwise healthy patients subjected to total hip replacement for severe osteoarthritis, the natural incidence, i.e., without prophylaxis, the distribution, and the location of deep vein thrombosis were studied. A further aim in this series of patients was to look at differences in thromboembolic complications between the two anesthetic techniques. The patients were randomly allotted to either “continuous” lumbar epidural anesthesia (n=48) or general anesthesia with parenteral analgesics after operation (n=46). The diagnostic methods employed were phlebography, pulmonary scintigraphy, and chest radiography. It was found that deep vein thrombosis occurred as a separate entity, with thigh vein thrombi isolated from calf vein thrombi. Thrombi in the thigh veins occurred almost exclusively on the side of operation, whereas thrombi in the calf veins were evenly distributed between the two legs. Pulmonary embolism occurred only in patients with phlebographic signs of thigh vein thrombi. Continuous lumbar epidural anesthesia significantly reduced the incidence of thigh vein thrombi (17 vs. 44%), thigh plus calf vein thrombi (65 vs. 83%), and pulmonary embolism (10 vs. 33%) as compared with intraoperative general anesthesia and parenteral analgesics used after operation. Blood loss was also significantly reduced during and after operation in patients with continuous lumbar epidural anesthesia. Lumbar epidural anesthesia prolonged into the postoperative period, in addition to other appropriate thromboprophylactic measures such as administration of dextran, should be of great value in patients undergoing major orthopedic hip surgery, which is associated with a very high risk of thromboembolic complications.