Preventing VTE After Elective TJA

Does overdiagnosis do more harm than good?
In the past, medicine was guided by expert opinion. Surgeons would perform procedures, then pass along their wisdom to the next generation. The initial literature in orthopaedics was filled with personal reports and case series. It is rumored that Sir John Charnley injected polyethylene into his own leg and found that it was inert, paving the way for one of the greatest modern medical inventions, low-friction arthroplasty.

Nowadays, society is driven by data, and an increasing number of data sources are being used to help guide medical care. This increase in available information has improved our ability to treat patients, and the AAOS routinely releases clinical practice guidelines (CPGs) and appropriate use criteria (AUCs) synthesizing the available evidence on given topics. These can be found online at www.orthoguidelines.org.

VTE prevention—what the evidence shows
As orthopaedic surgeons, we want to prevent potential complications. One example is the prophylactic use of antithrombotic treatment to reduce venous thromboembolism (VTE) after elective total hip and knee arthroplasty. VTE can occur after total joint arthroplasty (TJA) secondary to Virchow's triad, including endothelial injury, venous stasis, and a hypercoagulable state. Historically, the rate of VTE was higher, but over time, the incidence of VTE has decreased as rapid recovery protocols and increased postoperative mobility have decreased immobility and venous stasis.

In 2011, the AAOS published the CPG on "Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty." The AAOS Committee on Evidence-Based Quality and Value (EBQV), in collaboration with the work group chairs, also identified Impactful Statements. These statements call attention to those AAOS CPG recommendations that are both supported by strong or moderate evidence and diverge most from current practice. For the VTE CPG, the EBQV created the following Impactful Statement: Do not perform routine postoperative duplex ultrasonography screening in patients who undergo elective hip or knee arthroplasty (strong evidence).

This recommendation was considered impactful because it goes against dogma. In the past, many orthopaedic surgeons would routinely perform postoperative ultrasound screening in their primary TJA patients. They reasoned that catching and treating an asymptomatic superficial lower extremity thrombosis would be better than diagnosing a pulmonary embolism (PE). However, randomized controlled studies showed that applying routine ultrasounds after primary TJA did not reduce the rate of symptomatic PEs. Additionally, the over-diagnosis of deep vein thrombosis (DVT), especially superficial thrombosis (Fig. 1), in primary TJA patients can lead to over use of powerful anticoagulants. After surgery, these agents can lead to more devastating complications, such as hematoma formation, periprosthetic joint infection, and reoperation. Although occasionally indicated, ultrasound screening should not be performed in all patients after primary TJA.


Fig. 1 Superficial vein thrombosis after primary total joint arthroplasty diagnosed by duplex ultrasound screening.
Courtesy of Pekka Mooar

On the other hand, to prevent VTE after primary TJA, the use of mechanical compression with or without pharmacologic intervention is encouraged. However, studies have not shown whether these strategies affect rare, but critical, medical concerns such as mortality (ie, fatal PE) or symptomatic DVT or PE. No specific strategy of VTE prophylaxis is recommended, although the recent AAOS and American College of Chest Physicians (ACCP) guidelines added support for the use of aspirin in patients without significant risk of VTE.

To reduce the risk of postoperative bleeding, neuraxial anesthesia should be utilized in place of general anesthesia. Multiple randomized controlled trials support the use of different types of neuraxial anesthesia, without recommending one over others. While utilizing neuraxial anesthesia does not affect the occurrence of VTE after TJA, it does reduce the likelihood of bleeding, which may occur with the use of VTE prophylaxis.

Conclusion
As physicians, our goals are to help our patients and do no harm. By performing routine ultrasound screening on our patients, we may harm our patients by over treating asymptomatic DVTs without preventing symptomatic PEs. However, we can benefit our patients by utilizing neuraxial anesthesia during surgery, along with pharmacologic and/or mechanical prophylaxis after surgery to prevent VTE after primary TJA. Let's live the Hippocratic Oath when preventing VTE in our elective hip and knee arthroplasty patients.

Antonia F. Chen, MD, MBA, is a member of the AAOS Committee on Evidence-Based Quality and Value.

Advertisements

Advertisement