• Posted October 19, 2023

Extra Antibiotic With Hip, Knee Replacement Won't Prevent Infections: Study

Millions of people undergo joint replacement surgery every year. To prevent infection, doctors often give them a second antibiotic -- but new research suggests this can backfire.

Adding a second antibiotic at the time of hip and knee replacement surgery may actually increase infections, researchers in Australia found.

"Given the number of joint replacements performed in Australia and globally, our trial has answered the important about whether more antibiotics are better for our patients having joint replacement surgery: with the definitive answer being 'no,'" said study lead Trisha Peel, a professor of infectious diseases at Monash University's Central Clinical School.

"This trial will have a significant impact on practice,"Peel said in a university news release.

About 1% to 5% of patients get post-surgery infections, which results in serious health issues and death, her team noted.

The antibiotic cefazolin is currently used at the time of surgery to prevent infection.

Researchers studied adding vancomycin -- an antibiotic often used for MRSA (methicillin resistant Staphylococcus aureus) infections -- to the treatment plan.

Many medical centers globally have begun using both to prevent infections, despite the lack of clear benefit, according to this study.

This trial looked at more than 4,200 patients without a history of MRSA in 11 hospitals across Australia.

Patients were randomized to receive either vancomycin or saline placebo in combination with cefazolin.

The study found the addition of vancomycin was no better than the traditional cefazolin antibiotic.

Unexpectedly, in patients undergoing knee joint replacement, the risk of infection was higher in the group that had the added vancomycin, at almost 6%, than in the placebo group, with a roughly 4% infection rate.

"A lot of things seem to make sense, but we don't really know for sure until they are tested in a clinical trial,"Peel said. "This is one of those cases -- more antibiotics weren't better, and in some people might have actually been worse."

The study findings were published Oct. 18 in the New England Journal of Medicine.

More information

The U.S. National Institutes of Health has more on joint replacement surgery.

SOURCE: Monash University, news release, Oct. 18, 2023