Many orthopedic surgeons and dentists are routinely prescribing antibiotics to their joint implant patients before dental work despite guidelines to the contrary. That could be exposing many patients to adverse side effects from taking antibiotics they don’t need.

Early studies of joint implant outcomes suggested when dental work releases bacteria into the bloodstream, that bacteria can settle and grow on the artificial surfaces of joint implants or other orthopedic hardware. The infection could cause the implants to fail, requiring extensive and costly surgery to replace the hardware.

Those concerns led to recommendations that patients with implants take antibiotics before dental procedures up to two years post-surgery. Subsequent research has called that finding into question. The American Dental Association and the American Association of Orthopedic Surgeons issued new guidelines in 2015, saying that, except for a few high-risk categories, patients do not need to take preventive antibiotics.

“But too many orthopedists, particularly older orthopedists, say ‘I’ve always done it. My patients never get sick,’” said Dr. Mark Donaldson, a professor of pharmacy at the University of Montana in Missoula, and an associate professor in the School of Dentistry at the Oregon Health & Science University in Portland. “The evidence is very clear that it’s not required.”

Many orthopedic surgeons disagree, saying the research is inconclusive at best and they prefer to err on the side of caution. They may prescribe antibiotics more often than perhaps is needed to avoid a catastrophic failure of an implant. Some doctors even recommend their patients wear a medical alert bracelet so they don’t forget.

“It’s a difficult decision to come to because there’s not a lot of good research,” said Dr. Derrek Woodbury, an orthopedic surgeon with Desert Orthopedics in Bend. “We have some fairly good research out there, but unfortunately, it’s not good enough for us to make a solid recommendation.”

About 1 percent of patients will experience an infection after joint implant surgery, although the vast majority will occur within the first three months. It’s unclear, however, how often those infections are linked to dental work.

The 2015 guidelines were based primarily on four studies that compared patients with joint infections to comparable patients without infections to see if there was any difference in dental procedures between the two groups. All four of the studies found no increased risk of infection due to dental work. None of the studies were able to definitively answer the question.

Others argue that from a mere economic standpoint, it’s far more cost-efficient to prescribe everyone antibiotics than to pay $40,000 to $60,000 to replace an infected joint.

“I think our dental partners are quick to say you don’t need it. But some of who have been in it for a long time are a little weary,” said Dr. James Hall, an orthopedic surgeon at The Center: Orthopedic and Neurosurgical Care and Research in Bend. “We lean to the side of being conservative and giving them antibiotics. I think most dentists would agree with that.”

Dentists often feel caught in the middle, wanting to follow the guidelines from the American Dental Association but unwilling to overrule a doctor’s recommendation to patients.

“If they haven’t been told anything, we’ll go ahead and follow the updated guidelines,” said Dr. Eric Cadwell, a dentist with PureCare Dental in Bend. “But if their surgeon would like them to continue to take antibiotics prior to any dental procedure, then we’re happy to do that as well. It’s their call if they want to continue.”

A recent survey of dentists found that 70 percent reported inappropriate prescribing of antibiotics before a dental procedures.

Donaldson argues that prescribing antibiotics comes with downsides, as well. The medications can upset the normal mix of gut bacteria, leading to upset stomach, nausea or vomiting. Some patients will develop opportunistic infections such as oral thrush, or C. difficile, a gastrointestinal infection that can lead to severe, chronic diarrhea.

“A single innocuous 2-gram dose of amoxicillin really shouldn’t be a problem,” He said. “But you pick the wrong patient on the wrong day and it could be a life-threatening reaction.”

Public health officials have been urging doctors and dentists to be more judicious with antibiotic use to avoid creating resistant strains of bacteria. Antibiotic prescribing rates for dentists vary significantly across the United States. Oregon has one of the lowest rates in the country. Antibiotics before dental work are still recommended for many patients with heart conditions, including those with artificial heart valves.

According to a 2016 article in the Journal of Bone and Joint Surgery, the chances of a problem from the antibiotic are higher than the risk of joint infection from dental work. Evidence suggests the risk of an implant infection is higher from daily tooth brushing than that of a dental procedure. Regular visits to the dentists may have a protective effect. One study found that the risk of a joint infection is 30 percent lower in those who had visited the dentists at least once in the prior year.

The American Academy of Orthopedic Surgeons sought to bring clarity to the issue in 2016, developing new appropriate use criteria for antibiotics prescribing before dental work that helps doctors identify which patients may be at higher risk for infections. Doctors can input patients’ characteristics into a phone app and get recommendations on whether those patients would benefit from preventive antibiotics.

Those include patients with severely compromised immune systems due to AIDS, uncontrolled diabetes or chemotherapy or a recent history of joint infections, as well as patients taking specific drugs for rheumatoid arthritis or to prevent organ transplant complications.

Donaldson tells orthopedic surgeons if they want patients to take antibiotics before dental work, they should be the ones writing the prescription and facing the fallout.

“If anything untoward happens to that patient, you are going to be left out in the cold because you did something outside the current best practices,” he said. “The lawyers also have access to the guidelines.”

— Reporter: 541-633-2162, mhawryluk@bendbulletin.com