Moderator Berry: Okay, so a couple of areas of consensus. The data are stronger for or at least some benefit of antibiotic laden cement in the hip than the knee. In North America there’s not many cemented hips done any more so it may be less clinically relevant. And it seems like the knee is less well accepted at least in terms of the literature. Would you both agree with that statement?
Dr. Gehrke: Yes.
Moderator Berry: Now I heard both of you say that you had an area of consensus and that was the high-risk patient, undergoing surgery. You both said if you’re going to use cement, that is the patient who’s got immunosuppression, complex surgery, revision surgery … you’d use antibiotic laden cement. Did I get that correct from both of you?
Dr. Sculco: Yes, definitely.
Moderator Berry: There was consensus. But let me ask you the following question. If there’s a benefit to the high-risk patient, why wouldn’t you say that there is probably some benefit to the lower risk patient?
Dr. Gehrke: Of course, it’s true. If you are seeing a very good benefit for the high-risk patient there is, of course, benefit for the low risk patient at a lower level.
Dr. Sculco: I think so, but as I said, I think the downsides to the lower risk patient are greater. And I don’t think therefore its widespread use in that population is indicated.
Moderator Berry: About this question of antibiotic resistance, Thorsten, I think you’re probably right. The data is pretty weak. Our bacteriologist tells us that the likelihood of resistance emerging in a closed environment, like the hip or the knee—closed wound—is very, very low. Is that what your microbiologists say?
Dr. Gehrke: Exactly the same.
Moderator Berry: Tom, you did a nice job of bringing out this cost effectiveness question. What about mixing the antibiotic yourself and I’ll just say that’s an off-label use, but it’s far cheaper than using the pre-mixed stuff?
Dr. Sculco: There is a question as to whether the elution properties are as good if you hand mix it than if it’s commercially done. We did a study where we looked at using liquid gentamicin and the problem is that it is detrimental to the mechanical properties, but in a spacer, you can use liquid gentamicin for $3 for a little vial.
Moderator Berry: Tom, in your high-risk patient, what are you typically using for cement? Not brand names, but just in terms of what antibiotics?
Dr. Sculco: Palacos gentamicin is the one I would ordinarily use. If it’s a particularly high-risk patient that has a previous history of infection, I’ll probably add 500mg of vancomycin to that and mix it in.
Moderator Berry: Thorsten, how about you?
Dr. Gehrke: The same, absolutely the same. And if you are operating on a patient on a high risk or who has a history, for example, of MRSA infection, we use the industrially manufactured bone cement, which contains 1g gentamicin and 1g vancomycin.
Moderator Berry: That’s my pattern as well. Please join me in thanking the two speakers for a great session.
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