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So, in terms of risk stratification, there isn’t anything that says treatment “A” is better than treatment “B,” or that treatment “B” is better than treatment “C.” And that can have a huge impact on orthopaedic practice.Most academic medical centers probably already have some sort of guideline or protocol set up. The AAOS guidelines may or may not change their protocols. On the other hand, the AAOS guidelines will give them some supporting evidence that may help to limit their liability.

AAOS Now

Published 7/1/2007
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G. Jake Jaquet

PE is ‘ill-defined’ with no ‘clear-cut’ answers

The new clinical guidelines present a unique opportunity to determine the true incidence of symptomatic pulmonary embolism says Michael F. Schafer, MD.

The new clinical guidelines on the prevention of symptomatic pulmonary embolism (PE) in patients undergoing total hip or knee arthroplasty may be useful in changing protocols in some hospitals. But will they change behavior if hospitals don’t have mandated guidelines? AAOS Now Executive Editor G. Jake Jaquet spoke with Michael F. Schafer, MD, chair of the department of orthopaedic surgery at Northwestern University’s Feinberg School of Medicine, Northwestern Memorial Hospital.

Jaquet: What is your reaction to the new AAOS guidelines addressing prevention of symptomatic PE in patients undergoing total hip or total knee arthroplasty?

Schafer: The guidelines are long overdue and serve an important function. Unfortunately, PE is really an ill-defined medical problem—the cause of the problem is a huge unknown entity and there isn’t a clear-cut answer.

Previous guidelines have looked at the prevention of deep vein thrombosis and tried to pigeon-hole different situations and claimed that the recommendations were supported by Level 1, Grade A evidence. The advantage of the AAOS guidelines is that they focus on PE and show that, for that situation, there aren’t any Level 1, Grade A recommendations based on the literature.

Michael F.
Schafer, MD

The guidelines should be especially helpful for the community ortho-paedic surgeon who does 30 or 40 total hip or total knee arthroplasties a year, but really doesn’t have a large joint replacement practice, especially if he reads the part of the study that discusses the analytical methods that were used [Appendix III: Systematic Review Results]. That will certainly provide an educational benefit.

The drawback with the way that the new guidelines have been rolled out on the AAOS Web site is that they take time to understand. They’re lengthy and, as presented, they require careful study. But these PE guidelines involve life and death.

Jaquet: Does your hospital mandate a specific set of guidelines relative to the prevention of PE that orthopaedic surgeons must follow? What do you think the impact of the AAOS guidelines will be relative to your hospital and your surgeries?

Schafer: At Northwestern, we have certainly discussed PE and what to do about it, but the hospital has not mandated anything yet. We are really looking at this as a quality assurance measure. We have set up a team approach to anticoagulation in total hip and total knee arthroplasties. The hematology department, the in-house pharmacy group, and the total joint physicians all provide input. It’s essentially a dosing service, which we’ve had for a long time and is very important.

The dosing service follows patients throughout the preoperative, operative and postoperative periods. Most patients receive a warfarin protocol; we have used Lovenox® and we have had some postoperative bleeding problems. Very high-risk patients may receive Lovenox as a bridge until the warfarin kicks in, but we try to get them off of it as quickly as possible.

When patients are released, the dosing service continues to follow them. If a problem occurs—bleeding complications or anything along those lines—patients may go to a hospital near their home or come back to us. We make a huge effort to track our patients and we maintain an extensive database.

Will the new guidelines change our behavior patterns? I really don’t know. I’ve discussed then with other physicians here; all of us agree that the incidence of PE is small, that the new guidelines are sound, and that there isn’t one “right” methodology. The guidelines also point out that mechanical prophylaxis can and should be done.

Relative to the surgeries we perform at Northwestern Memorial, I don’t believe that the guidelines will alter our approach to PE. I think the guidelines point out what we already know from our work and our literature searches: that PE is ill-defined. In that respect, the new guidelines represent an exciting opportunity.

Jaquet: And that opportunity would be…?

Schafer: If we can engage the AAOS membership effectively, we have a chance to do what has never been done before—to find the true incidence of PE. Imagine a 3-year program. In the first year—and this could be tied to getting credits for Maintenance of Certification (MOC)—orthopaedic surgeons would look at outcomes in their own practices. What has been the incidence of PE? In the second year, AAOS could put together a DVD or some kind of program that would review the guidelines, test the surgeon, and provide credits for MOC. Then, participants would track their data for a year or so after they completed the initial program

to see if they changed their practice based on the guidelines and if that resulted in reducing the incidence of PE.

The key point of the guidelines is that nowhere do they say, “this is what you must do.” That is also the beauty of the guidelines. They acknowledge that the issue is really ill-defined.

Jaquet: So you think the AAOS should engage the membership and continue the work on developing clinical guidelines?

Schafer: Sure. What a great thing to do. If we can get AAOS members to really buy into evidence-based practice, we—as an organization—will have a positive impact on the community at large.