AAOS guideline rejects post-op ultrasound to screen for clots

The American Academy of Orthopaedic Surgeons (AAOS) has updated its clinical practice guideline to reduce the likelihood of blood clots after hip or knee replacement surgery, procedures that more than 800,000 Americans undergo each year. The new guideline advises against routinely screening patients after surgery using ultrasound imaging and suggests use of preventive treatments.

Thromboembolic disease—deep vein thrombosis (DVT) and pulmonary embolism (PE)—rarely causes symptoms.

According to the guideline, in the absence of prophylaxis, DVT occurs in about 37 percent of patients, as detected by imaging. The majority of those patients will remain asymptomatic and will require no further treatment. Recent studies in Denmark show that 0.7 percent of hip replacement patients and 0.9 percent of knee replacement patients require hospitalization because of DVT in the first three months after surgery, the AAOS said in statement.

The workgroup made these recommendations for care after hip or knee replacement:

• Hip and knee replacement patients should not have routine postoperative screening for thromboembolic disease with duplex ultrasound. Screening with this test does not significantly reduce the rate of symptomatic DVT or PE or the rate of fatal PE, the AAOS said.

•  Patients should receive anticoagulant therapy (unless they have a medical reason for not being able to use these drugs, such as a bleeding disorder or active liver disease) and/or mechanical compression devices after a hip or knee replacement surgery.

• After hip or knee replacement, patients should get up and walk as soon as safely possible. Although there is insufficient evidence that “early mobilization” reduces DVT rates, early mobilization is low cost, of minimal risk and consistent with current practice.

From the evidence reviewed, the workgroup made the following recommendations for physicians treating patients before hip or knee replacement:

• Patients should stop taking antiplatelet medications, such as aspirin and clopidogrel (Plavix), because of the increased risk of blood loss during surgery with these drugs.
• A patient should discuss the timing of stopping any medication with his or her physician.
• A prior DVT or PE is an additional risk factor for thromboembolic disease and it is important that a patient discuss any such event with his or her surgeon. There is insufficient evidence to recommend for or against routinely assessing patients for other possible risk factors.
• Patients may want to have the surgery performed under regional anesthesia, such as epidural or spinal, rather than general anesthesia. Although evidence suggests that these regional approaches do not affect the occurrence of DVT or PE, they do limit blood loss.

The workgroup also outlined suggestions for future research to fill in the evidence gaps that were apparent through an exhaustive and systematic review of the medical literature. Further research is deemed critical to develop the optimum strategies to prevent venous thromboembolic disease in the safest and most effective manner.

To view the full guideline, “Preventing Venous Thromboembolic Disease in Patients Undergoing Elective Hip and Knee Arthroplasty,” click here.