Venous thromboembolic disease after total hip and knee arthroplasty : current perspectives in a regulated environment

Venous thromboembolic disease is the single most common reason for readmission to the hospital following total hip and total knee arthroplasty and remains a genuine threat to the life of the patient. Nevertheless, advances in surgical procedure, anesthetic management, and postoperative convalescence have altered the risks of venous thromboembolism after total joint arthroplasty in the lower extremity. Regional anesthetic techniques reduce the prevalence of venographic thrombosis by approximately 50%, and intraoperative monitoring has identified preparation of the femoral canal as the sentinel event that activates the coagulation cascade by the intravasation of marrow fat into the systemic circulation. Prevention of venographic thrombosis is most efficacious by administering fractionated heparin followed by warfarin; warfarin (international normalized ratio 2.0) appears to have a greater safety margin than fractionated heparin based on clinically meaningful bleeding events. Prevention of readmission events, proximal thrombosis, or pulmonary embolism has been demonstrated by using low-intensity warfarin. Aspirin, when used in conjunction with hypotensive epidural anesthesia after hip arthroplasty and regional anesthesia after knee arthroplasty, combined with pneumatic compression devices, also has been suggested to prevent clinical venous thromboembolism, as measured by readmission events. Oral thrombin inhibitors hold promise, but instances of liver toxicity have precluded approval in North America to date. Mechanical compression devices enhance venous flow and increase fibrinolytic activity in the lower extremity; clinical trials demonstrate efficacy in reducing venographic thrombosis alone after total knee arthroplasty and in combination with other chemoprophylactic agents after total hip arthroplasty. Extended chemoprophylaxis for 3 to 6 weeks after surgery is prudent in view of the protracted risk of thrombogenesis and the late occurrence of readmission for venous thrombosis and pulmonary embolism