The rate of deep infections following revision hip and knee arthroplasty is increasing and will continue to rise unless action is taken, according to new data presented at the annual meeting of the Orthopaedic Research Society in Chicago.¹

The new research comprised 14 years' worth of data from the Nationwide Inpatient Sample, which captures about 20% of all US hospitalizations each year. The new findings, however, only provide a conservative estimate of the infection burden and do not quantify risk of infection.

"There is a general increasing trend in overall reported or diagnosed infections following revision arthroplasty," says lead researcher Steven M. Kurtz, PhD, office director and principal engineer at Exponent Failure Analysis Associates in Philadelphia, Pennsylvania. Specifically, in 1990, there were 1000 infections following revision knee arthroplasty, and this number climbed to 5000 by 2003. The infection burden is similar for hips, the data show. In general, infection burden following revision hip or knee arthroplasty is .5% to 1%, depending on the size of a hospital or center.

"The take-home message is that infection risks are not going down with time and there needs to be improved research or attention to address the infection risk on a national level," Dr. Kurtz tells CIAOMed. "Infections can happen, [but] there are medical devices out there like antibiotic bone cement that could potentially help [prevent them]. This is not a stagnant problem, but an unsolved problem, and it's not something you can be an ostrich about [addressing].

"By 2030, revision surgery will go up quite a bit, and infections are becoming more prevalent, so unless something happens, we will just see more and more infections," Dr. Kurtz predicts.

Reasons for rise remain unclear

While the new study did not identify the reasons for the increase in infection burden following revision arthroplasty, Dr. Kurtz speculates that "more resistant bugs could be one reason, and more people are looking at minimally invasive surgeries, which may have longer surgical times and [thus] may be associated with a higher risk of infection," he says. Alternatively, "we may simply be more sensitive to infections and code for them more frequently."

Cost of treatment is stagnant

While the rate of infection burden increased during the years studied, the cost of treatment did not, says Dr. Kurtz. "Infections are just as expensive today as [they were] in the early 1990s, and that's something I did not expect to see." Moreover, the new research suggests that infections are more likely to be seen in urban teaching hospitals than in other hospital settings.

"These infections are so devastating to treat from a financial perspective that small hospitals refer them out to big and large centers [that] have more experience with difficult-to-treat infections," explains Dr. Kurtz.

Reference

1. Kurtz S, Lau E, Schmier JK, et al. Nationwide infection burden in revision hip and knee arthroplasty. Presented at: 52nd Annual Meeting of the Orthopaedic Research Society. March 18–22, 2006; Chicago, Ill. Abstract 235.