Orthopedic Teaching Cases 2023, Jan, 20 | 12:00 am

Reconstruction Cases AAOS guidelines on preventing VTE

A 67-year-old woman who is scheduled to undergo primary total hip arthroplasty for end-stage arthritis of the right hip calls your office to inform

you that she just remembered that 15 years ago she had a blood clot after a long plane flight. She asks if this event will affect her scheduled surgery or expected postoperative course. You inform her that based on the 2011 AAOS guideline on preventing venous thromboembolic disease in patients undergoing elective total hip and knee arthroplasty:

  1. There is strong evidence to support increasing the duration of her postoperative pharmacologic prophylaxis to at least 6 weeks because of her history of DVT

  2. Her history of DVT makes her too “high risk” to undergo elective surgery and the procedure will have to be cancelled

  3. She will be placed on warfarin postoperatively because it is more effective at preventing VTED than other forms of pharmacologic prophylaxis

  4. A personal history of DVT does not increase the risk of VTED following elective hip and knee arthroplasty

  5. She will receive both pharmacologic and mechanical prophylaxis in the postoperative period because of her history of prior deep venous thrombosis

Discussion

The correct answer is (E). Determining appropriate VTED prophylaxis remains a challenge in the setting of elective total hip and knee arthroplasty. There is no evidence regarding the optimal duration of pharmacologic prophylaxis in patients with a prior history of DVT and this remains an area of controversy that must be addressed on a case-by-case basis after discussion of the potential risks and benefits with the patient (choice A). The relative efficacy of different types of prophylaxis has been investigated, and there is not strong evidence to support the use of one pharmacologic agent over another (choice C). A personal history of DVT is the only risk factor known to increase the likelihood of VTE following total hip or knee arthroplasty (choice D); however, the relative increase in risk is not great enough to make proceeding with surgery unsafe (choice B). It is a consensus opinion in the 2011 AAOS guideline on preventing VTE that patients with a history of DVT be treated with both pharmacologic and mechanical prophylaxis (choice E).

Which of the following interventions are not supported by either consensus opinion or moderate scientific evidence in the 2011 AAOS guideline on preventing venous thromboembolic disease in patients undergoing elective total hip and knee arthroplasty?

  1. Patients should discontinue antiplatelet agents (e.g., aspirin, clopidogrel) 5 to 7 days prior to elective total hip or knee arthroplasty

  2. Early mobilization is an important adjunct in the prevention of VTED in patients undergoing elective total hip or knee arthroplasty

  3. The use of neuraxial anesthesia decreases the risk of VTED when compared to the use of general anesthesia in elective total hip or knee arthroplasty

  4. Routine postoperative screening duplex ultrasonography is not indicated in patients undergoing elective total hip or knee arthroplasty

Discussion

The correct answer is (C). The optimal time for discontinuation of antiplatelet agents has not been studied specifically in arthroplasty patients, but among nonarthroplasty patients there are multiple studies demonstrating increased operative blood loss in patients that did not stop antiplatelet agents prior to elective surgery (choice A). Early mobilization is a low-cost, low-risk intervention that promotes regional blood flow, so despite a lack of strong evidence, it is supported by AAOS consensus opinion (choice B). Studies comparing screening with venous ultrasonography with no screening do not show a significant difference in the rate of pulmonary embolus or hospital readmission for DVT in those patients who underwent routine screening (choice D). Multiple moderate/high-quality studies demonstrate no significant difference between the rates of VTED between neuraxial and general anesthesia (choice C).

 

Objectives: Did you learn...?

 

The consensus opinion of the 2011 AAOS guidelines on preventing VTE