Risk factors for venous thromboembolism in orthopedic surgery.

Venous thromboembolism is a recognized complication of trauma and elective orthopedic surgery with significant mortality and morbidity [1,2]. The silent nature of the disease and the notorious difficulty in clinical diagnosis, along with the high prevalence among orthopedic patients, justifies the need for thromboprophylaxis. Despite the publication of consensus guidelines advocating routine prophylaxis [1±3] there is still reluctance by some orthopedic surgeons to use it [4]. Furthermore, a significant number of patients still die from fatal pulmonary embolism after elective total hip replacement despite the use of the best available antithrombotic agents ± currently between 30 and 40 patients per 10,000 post-total hip replacements [3]. The belief that routine thromboprophylaxis is mainly justified by the reduction in the rate of fatal PE [4] does not address the non-fatal complications of deep vein thrombosis. There is significant risk of long-term morbidity from post-thrombotic venous insufficiency and chronic venous ulcers. The concern over bleeding is often given as the main reason for withholding therapy. There is an increase in bleeding as compared to placebo-control populations, but no increase in associated morbidity or mortality. In particular, wound complications including infection have not been found to be increased in prospective comparative studies. Sequential changes from unfractionated heparin and low molecular weight heparin to more efficacious agents such as pentasaccharides [5,6] have not been associated with an increase in wound complications. The clinical benefit and cost-effectiveness of thromboprophylaxis can be maximized by accurate assessment of patients' risk factors for the development of VTE [7]. This allows selective use of specific agents and regimens to those most at risk. The present article reviews the current understanding of risk factors for venous thromboembolism in orthopedic surgery, which can be broadly divided into the operative setting and patient factors.