Now, what about emergent bacteria? Certainly, mutation in organisms is a problem.
Some quotes from microbiologists and people who study this: “As might be expected from Darwinian evolution antimicrobial usage exerts a selective pressure favoring the emergence of antibiotic resistant organisms.” Another economist and microbiologist: “Antimicrobial resistance is driving up healthcare costs, increasing the severity of disease and increasing the death rate from certain infections.”
An organism can, in fact, grow on these antibiotic-loaded bone cements and can be exposed at sub-inhibitory levels, which induces bacterial mutation.
Looking at revision surgery, when primary bone cement with antibiotics was used, 88% had gentamicin resistant bacteria. They mutated very quickly. By contrast, in 57 revisions where antibiotic cement was not used in the primary, only 16% had resistant organisms.
A very, very good study by the Canadian government which looked at randomized trials, meta-analysis and systematic reviews concluded that “antibiotics in cement may not confer any benefit over plain cement in total knee and total hip.”
The Norwegian registry, which was quoted, you need to reduce the infection rate 2.4-fold for it to be cost effective.
The Australian registry, which Thorsten just mentioned, 100,000 total knees, risk of revision for infection same with or without the use of antibiotics in cement.
Kaiser registry, 26,000 total knee replacements, no difference in infection rate with or without antibiotics,
So, in summary, I think the problems are that it is not cost effective, it can increase bacterial resistance (I think that is a real potential problem) and it’s primarily useful in that high risk primary or revision knee.
Moderator Berry: Thorsten, any quick rebuttal?
Dr. Gehrke: First of all, I accept, for example, your cost issue in the U.S. We don’t have it in Germany. The development of resistance of the organism was based on just two papers – again, never proven. Very low numbers. Fourteen cases. One other comment, we should differentiate between hip and knees. All Australian registry data were about knees. And the hip literature is a little bit different.
Dr. Sculco: I think you’re absolutely right, Thorsten. If you look at the registry studies that you were quoting that were used in Scandinavia and the UK, the results are better in the hips than the knee, no question.
