Routinely giving patients with joint replacements antibiotics before undergoing dental procedures to prevent possible infection has long been the standard of care. But now, two major medical organizations are suggesting a possible step back from that common practice – for healthy patients. The American Academy of Orthopaedic Surgeons (AAOS) and the American Dental Association (ADA) have issued a joint clinical practice guideline that finds insufficient evidence to recommend such routine antibiotic use.

“The theory is, bacteria come through the bloodstream [from the dental work],” says David Jevsevar, MD, chair of the AAOS Evidence Based Practice Committee and an orthopaedic surgeon in St. George, Utah. “Does it increase the risk of infection in joint replacements? The honest answer is, we don’t know. We know that dental work puts bacteria in the bloodstream. What we don’t know is how often bacteria gets into the joints.”

The guideline notes that around a million hip and knee joint replacements were performed in the United States in 2010, and the mean rate of joint infection after the surgery was 2 percent. The clinical research that backs up the guideline finds invasive dental procedures, with or without antibiotics, did not increase the risk of infection in a prosthetic joint.

The guideline – which notes that “no direct evidence” exists that oral or topical antibiotics confer any protection against infection in a replaced joint – therefore recommends oral care professionals reconsider routine use of antibiotics before dental procedures.

But experts say that some joint replacement patients – those with inflammatory joint diseases such as rheumatoid arthritis (RA) and lupus, those on immunosuppressive drugs such as corticosteroids and disease-modifying antirheumatic drugs (DMARDs), and those who’ve had more than one joint replacement – should still get prophylactic antibiotics.

Dr. Jevsevar says the original recommendation to use antibiotics in those who had undergone replacement arthroplasty, or surgery, was basically an extension of what had become traditional practice for patients with heart valve replacements. In both cases, mechanical devices replace natural body structures – and that means they are more vulnerable to bacterial attack. (Although in some heart valve procedures, natural tissues may be used.)