Thrombosis prevention after total hip arthroplasty: a prospective, randomized trial comparing a mobile compression device with low-molecular-weight heparin.

BACKGROUND: Thromboembolic disease is a common complication of total hip arthroplasty. The purpose of this study was to compare a new mobile compression device with low-molecular-weight heparin with regard to their safety and effectiveness for the prevention of venous thromboembolic disease.

METHODS: Patients who had a total hip arthroplasty were randomized to receive prophylaxis with a mobile compression device or low-molecular-weight heparin for ten days. Use of the compression device began intraoperatively, and the patients in this group could receive 81 mg of aspirin daily after the surgery. The first injection of the low-molecular-weight heparin began between twelve and twenty-four hours after the surgery. After ten to twelve days, all patients underwent bilateral lower-extremity duplex ultrasonography to screen for deep venous thrombi in the calf and thigh. Any clinical symptoms of pulmonary embolism were evaluated with spiral computed tomography lung scans. Bleeding events and utilization of (i.e., compliance with) prophylactic treatment in both groups were documented. Clinical evaluation to look for evidence of deep venous thrombi and pulmonary emboli was performed at twelve weeks postoperatively.

RESULTS: Four hundred and ten patients (414 hips) were randomized; 392 of these patients (395 of the hips) were evaluable with regard to the safety of the intervention and 386 patients (389 hips) were evaluable with regard to its efficacy. Demographics were similar clinically between the groups. The rate of major bleeding events was 0% in the compression group and 6% in the low-molecular-weight heparin group. The rates of distal and proximal deep venous thrombosis were 3% and 2%, respectively, in the compression group compared with 3% and 1% in the heparin group. The rates of pulmonary embolism were 1% in the compression group and 1% in the heparin group, and there were no fatal pulmonary emboli. Within the twelve-week follow-up period, two events (one deep venous thrombosis and one pulmonary embolus) occurred in one patient in the compression group following negative findings on duplex ultrasonography on the twelfth postoperative day. There was no difference between the groups with regard to the prevalence of venous thromboembolism.

CONCLUSIONS: When compared with low-molecular-weight heparin, use of the mobile compression device for prophylaxis against venous thromboembolic events following total hip arthroplasty resulted in a significant decrease in major bleeding events.