Methods

We conducted an independent prospective study comparing VTE prevention strategies in two successive series of patients (Groups A and B) undergoing elective unilateral THR. Group A (n=253) received fondaparinux daily 2.5 mg for 10 days, followed by tinzaparin 4500 IU daily for one month. Group B (n=229) received 10 mg rivaroxaban daily for 40 days without platelet monitoring.

All surgeries were performed by a single surgeon under general anesthesia using an active blood transfusion-sparing plan. In the absence of contraindications, patients received intra-operative administration of tranexamic acid to reduce postoperative bleeding.

Preoperative and postoperative hemoglobin levels were recorded at regular intervals. Bleeding events were documented. The bleeding index was calculated by adding the number of red blood cell units and the difference in the hemoglobin level (in g/dL) between the first morning after the day of surgery and the seventh postoperative day (POD 7). After 5 to 10 days, all patients underwent bilateral lower-extremity duplex ultrasonography to screen for deep venous thrombi. Any clinical symptoms of pulmonary embolism were evaluated with spiral computed tomography lung scans. Clinical evaluation to look for evidence of deep venous thrombi and pulmonary emboli was performed at eight weeks postoperatively.