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Hip and Knee Replacement Surgery – DVT Prophylaxis – AAOS Guideline

Two main guidelines exist which many physicians go by to decide whether a particular patient should get DVT prophylaxis after hip or knee replacement surgery, what method (compression device, or pharmacologic agent) to use, and for how long to give prophylaxis.  (a) One is the ACCP guideline (American College of Chest Physicians), last published in June 2008 [ref 1].  An updated version is expected to be published around February 2012.  (b) The other one is the AAOS guideline (American Academy of Orthopedic Surgeons), last published in August 2008, but just updated last week (link here) [ref 2].


The key points from the new AAOS guideline

  1. History of previous venous thromboembolism predicts a higher risk of another VTE with hip or knee replacement surgery. However, it is unclear whether other risk factors (overweight, smoking, being on estrogens, having a thrombophilia, etc.) predict a higher risk of VTE with these surgeries.
  2. It is suggested that patients WITHOUT a personal history of  VTE should either receive (a) mechanical/compressive devices, or (b) a pharmacologic agent.  The guideline states that it is unclear (a) which method is better, and (b) how long preventive therapy/measures should be given/employed after the surgery.
  3. The consensus of the working group is that patients WITH a personal history of VTE should get mechanical compression devices AND a pharmacologic agent.
  4. Patients with bleeding disorders should get mechanical, not pharmacologic DVT prophylaxis.
  5. A routine Doppler ultrasound after the surgery upon discharge from the hospital should not be done.

The AAOS press release can be found here. 

My Conclusion

In spite of this being an 824-page thick document, no specific clinical guidance is given as to what DVT prophylaxis is best to give to a patient.  The conclusion really is that there are many acceptable treatment options.  The term “pharmacoloigc agent” in the guideline is not defined, and, thus, can mean aspirin or any of the anticoagulants. In short:

  • In patients without a history of VTE, MDs can give any of the following prevention therapies that they and their patients decide on:  a mechanical device, aspirin, low molecular weight heparin, unfractionated heparin, fondaparinux, warfarin or rivaroxaban – at any dose and for any length of time they decide on.  All are acceptable options.
  • The patient with a history of VTE should get a mechanical device PLUS some pharmacologic agent (aspirin, low molecular weight heparin, unfractionated heparin, rivaroxaban, fondaparinux, or warfarin).  Again, dose, frequency and duration of therapy can be freely decided on.  All are acceptable options.


  1. Geerts WH et al. Prevention of venous thromboembolism. American College of Chest Physicians evidence-based clinical practice guidelines (8th edition). Chest 2008;133:381S-453S.

Disclosure: I have consulted for Ortho McNeil and Bayer (who develop Rivaroxaban)

Last updated: Sept 30th, 2011

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