PROPHYLAXIS FOR DEEP-VEIN THROMBOSIS WITH ASPIRIN OR LOW-MOLECULAR-WEIGHT DEXTRAN IN KOREAN PATIENTS UNDERGOING TOTAL HIP-REPLACEMENT - A RANDOMIZED CONTROLLED TRIAL

150 Korean patients undergoing primary uncemented total hip replacemen t were randomized into 3 treatment groups for deep vein thrombosis (DV T) prophylaxis. Group A(50) Mere controls; Group B(50) received aspiri n 1.2 g daily in 3 divided doses from 2 days before, to 14 days after surgery; Group C(50), received low molecular weight dextran 500 ml, in fused intravenously at 50 ml/hour during surgery, and on each of the f ollowing 2 days. Contrast venograms were performed prior to surgery an d 7-10 days after: The incidence of DVT was 20% in the control group, 12% in the aspirin group (p <0.1 vs control), and 6% in the dextran gr oup (p <0.05 vs control). In patients developing DVT the ratio of prox imal to distal thrombi was increased in the control group as compared to treated groups (4:1 in the control group vs 1.5:1 in the treated gr oups). Both aspirin and dextran were well tolerated. Obesity (p <0.05) and long-term administration of steroids (p <0.05) were risk factors for deep vein thrombosis which reached statistical significance in the control group. Intraoperative venograms performed on 10 patients, sho wed that hip flexion (mean 40.4 degrees) plus adduction (mean 11.5 deg rees) plus internal rotation (mean 81.5 degrees), resulted in severe t wisting or kinking of the femoral vein with stagnation of blood flow. Low molecular weight dextran significantly reduce the incidence of dee p venous thrombosis and aspirin, though less effective, had a similar effect. Internal rotation of the hip joint should be minimized during operation in order to limit stagnation of bloodflow in the femoral vei n.