Patient Education Blog

Hip and Knee Replacement – DVT Prevention – New 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 drug) 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 clot (DVT or PE) predicts a higher risk of another clot with hip or knee replacement surgery. However, it is unclear whether other risk factors (overweight, smoking, being on estrogens, having a clotting disorder, etc.) predict a higher risk of clots with these surgeries.
  2. It is suggested that patients WITHOUT a personal history of blood clots (venous thromboembolism) should either receive (a) mechanical/compressive devices, or (b) a medication (“pharmacologic agent”)  that prevents blood clots. 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. It dose not take reference as to what “pharmacologic agents” can be used.
  3. The consensus opinion of the working group is that patients WITH a personal history of blood clots (venous thromboembolism) should get mechanical compression devices AND a medication (“pharamcologic agent”) to prevent clots.
  4. Patients with bleeding disorders should get mechanical DVT prophylaxis, not medications.
  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” is not defined, and, thus, can mean aspirin or any of the blood thinners (anticoagulants).  In short:

  • In patients without a history of blood clot, 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 blood clots should get a mechanical device PLUS some medication (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.

 It will be interesting to see how the new ACCP guidelines in 2012 compare to the above AAOS guideline.


  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

Disclaimer:, its contributors, authors, advisors, members and affiliate organizations do not assume any liability for the content of the website, blog and educational materials. Medical information changes rapidly. While information is believed to be correct, no representation is made and no responsibility is assumed for the accuracy.

Tags: , , , , , , ,

This entry was posted by clotconnect on at and is filed under Prevention. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

Comments are closed.