Rivaroxaban, dabigatran, apixaban and edoxaban are the four available new oral anticoagulants (NOAC) which are currently approved for venous thromboembolism prophylaxis after total hip and knee replacement. Large phase 3 and phase 4 studies comparing NOAC with low molecular weight heparins have shown similar results regarding the efficacy and safety of these two categories of anticoagulants. Management of bleeding complications is a matter of great significance. Three reversal agents have been developed: idarucizumab, andexanet alfa and ciraparantag. Idarucizumab is now commercially available. Regarding the perioperative management of NOAC, two main scientific groups have published their own recommendations. The European Heart Rhythm Association recommends 48-h period of stoppage preoperatively for factor Xa inhibitors and at least 3 or 4 days for dabigatran, while the French Study Group on Thrombosis and Haemostasis recommends 5-day discontinuation for all NOAC. Conventional clot tests can only be used as rough indicators for laboratory assessment of the activity of NOAC. Specific laboratory tests have been developed for more accurate measurements of NOAC blood levels, including a dilute thrombin time test (Hemoclot test) and the ecarin clot test for dabigatran and chromogenic anti-factor Xa assays for direct factor Xa inhibitors. Due to the beneficial properties of NOAC, these drugs are gaining ground in daily orthopaedic practice, and many studies are being conducted in order to extend the indications of these anticoagulants agents.
Keywords: Laboratory assessment; New oral anticoagulants; Orthopaedics; Perioperative management; Reversal agents.