THROMBOEMBOLIC COMPLICATIONS AFTER TOTAL HIP ARTHROPLASTY: COST-EFFECTIVENESS OF SYSTEMATIC SCREENING

Abstract

Purpose of the study: Thromboembolism is a serious complication after hip surgery. The residual rate of venous thrombosis has varied according to the type of screening used with rates reported from 3.54% to 54.2% without prophylaxis. These discordant figures led us to conduct a prospective study devoted to thromboembolic complications.

Material and methods: This prospective study was conducted from April 1995 to April 1996 in 61 consecutive patients who underwent total hip arthroplasty under general anesthesia. Duplex Doppler was performed systematically on day 8 to 10 to search for thromboembolic complications. Results of this study were compared with those of a study we conducted in 2960 total hip arthroplasties implanted from 1950 to 1999 where search for thromboembolic complications was guided by the clinical presentation.

Results: Clinical screening for thromboembolic complications in the series of 2960 total hip arthroplasties revealed a rate of 3.54% [pulmonary embolism (n=46), phlebitis (n=95), heparin induced thrombopenia (n=14)]; the rate of anticoagulant accidents was 2.5%. Associating these anticoagulant accidents with the cases of heparin induced thrombopenia, the rate of these complications was 2.97%, almost the same as that of thromboembolic complications. Duplex Doppler screening on day 8–10 detected venous thrombosis in 36.8% of patients.

Discussion: Thromboembolic complications with clinically detected phlebitis confirmed by duplex Doppler were observed in 3.54% of our series of 2960 operated patients, but systematic screening with duplex Doppler found a ten-fold higher rate, 36.8%. Should duplex Doppler be performed systematically in the postoperative period? What would be the cost, and the cost-effectiveness? It is known that when phlebitis is detected, anticoagulant treatment must be continued for at least three months postoperatively. In addition, the cases of phlebitis detected by duplex Doppler are generally distal, with no clinical expression; so what would be the benefit for these patients of long-term treatment? Considering the expenditures involved in 1000 total hip arthroplasties treated preventively with low-molecular-weight heparin, the cost of systematic duplex Doppler screening would lead to a supplementary cost of 456000 euros, without counting the cost of treatment for complications due to the anticoagulant treatment.

Conclusion: In our opinion, systematic duplex Doppler screening is not warranted. We believe that clinical screening is a valid procedure, in line with evidence provided by duplex Doppler performed in symptomatic patients. Anticoagulant treatment should be continued for six weeks after the arthroplasy as a preventive measure and should be initiated 12 to 24 hours after the operation. Systematic ultrasound screening is only useful in high-risk patients or when thrombosis prophylaxis cannot be instituted.