New Oral Anticoagulants After Total Knee Arthroplasty

Clinical Considerations for Orthopaedic Surgeons

James Kudrna

Disclosures

Curr Orthop Pract. 2013;24(4):424-432. 

In This Article

Abstract and Introduction

Abstract

Patients who undergo total knee arthroplasty are at risk of developing venous thromboembolism. Thromboprophylaxis is widely accepted as standard of care in patients receiving total knee arthroplasty, but implementation of clinical practice guidelines is hampered by several barriers, including limitations of current agents. New anticoagulants in clinical development offer equivalent or superior efficacy and safety to existing anticoagulants and the added convenience of oral administration. To date, rivaroxaban is the only new oral anticoagulant with regulatory approval for total knee arthroplasty in the United States, although dabigatran and apixaban are approved in other countries. For total knee arthroplasty, neuraxial blockade offers advantages over general anesthesia and narcotic-based systemic analgesia, but it carries a risk of spinal hematoma if used in conjunction with antithrombotics. Clinical practice guidelines already exist for the use of neuraxial blockade with traditional antithrombotics, and similar evidence-based recommendations are required for the new oral anticoagulants.

Introduction

Total knee arthroplasty (TKA) is one of the most common orthopaedic procedures in the United States (US), with approximately 500,000 surgeries performed annually.[1]

For many patients, neuraxial blockade (spinal or epidural anesthesia and continuous epidural analgesia) is an option that has demonstrated significant reductions in cardiac and pulmonary morbidity, bleeding, and improved joint mobility after major knee surgery compared with general anesthesia or narcotic-based systemic analgesia.[2] Neuraxial blockade also offers superior pain control and patient satisfaction.[2] However, neuraxial blockade carries a small but significant risk of spinal epidural hematoma, which may lead to spinal cord ischemia and paraplegia. The incidence of neurologic dysfunction resulting from neuraxial blockade -associated hemorrhagic complications is unknown but is estimated to be 1 in 150,000 for epidural anesthesia and 1 in 220,000 for spinal anesthesia.[3] Several risk factors have been linked to a higher incidence of spinal epidural hematoma in patients receiving neuraxial blockade, including underlying hemostatic disorders, anatomic vertebral column abnormalities, traumatic needle or catheter insertion, and advanced age.[2] Another important risk factor is the concomitant use of antithrombotics.

Thromboprophylaxis is widely accepted as standard of care in patients receiving TKA.[2,4] Venous thromboembolism (VTE; pulmonary embolism [PE] and deep vein thrombosis [DVT]) is a devastating and potentially lethal complication associated with orthopaedic surgery. In the absence of thromboprophylaxis, incidences of DVT and PE are reportedly 41–85% and 1.5–10%, respectively, after TKA.[2] Symptomatic PE is rapidly fatal in approximately 10% of patients, and a further 5% of patients will die at a later stage.[5] VTE is associated with significant complications such as postthrombotic syndrome (PTS), chronic thromboembolic pulmonary hypertension (CTPH), and an increased risk of recurrent events.[6]

Prophylaxis with traditional anticoagulants reduces the cumulative incidence of symptomatic VTE to 2.3% within 3 months of TKA,[7] but the risk remains significant, and this has driven the development of new anticoagulants. New anticoagulants offer advantages, in terms of efficacy, safety, and convenience, compared with traditional agents. However, while some clinical practice guidelines have attempted to address the use of traditional anticoagulants in patients receiving neuraxial blockade,[3,8] the risks associated with newer agents and neuraxial blockade are largely uncharacterized.

Balancing the advantages and risks of new anticoagulants with the benefits of neuraxial blockade will be essential if we are to ensure the best possible outcomes for patients who undergo TKA.

This clinical practice overview will discuss the prevention of VTE after TKA, and best practice for neuraxial blockade in conjunction with thromboprophylaxis. Current practice guidelines will be discussed, as will the limitations of traditional antithrombotics, and the promise of new and investigational agents.

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