Abstract
Thromboembolic disease (TED) remains as a major concern for orthopaedic surgeons and is a well-known complication of lower extremity joint replacement procedures. While there is voluminous literature on the topic, it is difficult for the average orthopaedic surgeon to keep up with all the advancements in this area as well as the newer pharmacological options for prophylaxis. To address this, the American Academy of Orthopaedic Surgeons (AAOS) has developed a clinical practice guideline (CPG) in this area to provide treatment recommendations based on the best available evidence. Historically, guidelines for TED prophylaxis have been based largely on randomised controlled trials whose outcome measure was venographically documented deep vein thrombosis (DVT). However, many venographically documented DVTs, particularly those distal to the popliteal vein, are of no clinical consequence. Therefore, in the AAOS CPG the systematic review of the literature was focused on those outcomes that have the most clinical relevance: all-cause mortality, symptomatic or fatal pulmonary embolism (PE), proximal DVT, major bleeding and symptomatic DVT rates.
Using these as the clinically important endpoints, it is evident that the extant literature is insufficient to provide definitive guidance in this area and to make specific recommendations about optimal pharmacological prophylaxis. Nonetheless, one strong recommendation has emerged from this systematic review: the guideline recommended against routine post-operative duplex ultrasonography screening of patients who undergo elective hip or knee arthroplasty. Only one risk factor – previous history of TED – had evidence demonstrating a higher risk beyond the risk from elective hip or knee arthroplasty itself (weak recommendation). There was not sufficient evidence that other potential risk factors increase the risk of TED, likely because of the relatively high background risk of elective hip or knee arthroplasty. In addition, there is very little evidence defining populations at increased risk for bleeding and bleeding-associated complications associated with pharmacological prophylaxis. However, the panel did come to a consensus that patients with known bleeding disorders or active liver disease are at an increased risk for post-operative bleeding. In these circumstances, it is recommended that mechanical compressive devices be the primary modality of prophylaxis as pharmacologic prophylaxis may increase the risk of bleeding.
There was a moderate strength recommendation for the superiority of neuraxial anesthesia to limit blood loss even though there is no demonstrable effect on the incidence of TED. Finally, there was a moderate grade recommendation that pharmacologic agents (including aspirin) and/or mechanical compression devices be utilised for the prevention of VTE in patients that are undergoing elective hip or knee arthroplasty who are not at elevated risk beyond that of the surgery itself for VTE or bleeding. Clearly there is great need for better evidence with appropriately powered studies that examine the most clinically relevant outcomes in TED prophylaxis.
