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For several years, orthopedic surgeons and dentists have given conflicting advice about whether a patient with prosthetic joint implants needs antibiotics to prevent potential infections – a practice known as antibiotic prophylaxis (iStockphoto)
For several years, orthopedic surgeons and dentists have given conflicting advice about whether a patient with prosthetic joint implants needs antibiotics to prevent potential infections – a practice known as antibiotic prophylaxis (iStockphoto)

I have an artificial knee joint – should I take antibiotics before the dentist? Add to ...

The question

When my knee was replaced with an artificial joint, the surgeon said I should always take antibiotics before any dental procedure. He said the bacteria in my mouth could get into my bloodstream and cause an infection around the implant. But my dentist said not to worry and that I actually don’t need antibiotics. Who is correct?

The answer

For several years, orthopedic surgeons and dentists have given conflicting advice about whether a patient with prosthetic joint implants needs antibiotics to prevent potential infections – a practice known as antibiotic prophylaxis. The surgeons believed that antibiotics were necessary because a joint infection could jeopardize the implant. Dentists, on the other hand, felt that mouth bacteria didn’t pose a risk to the implants and patients shouldn’t be taking the drugs needlessly.

The mixed messages have certainly caused confusion for patients. But, thankfully, dentists and surgeons have finally settled their differences and come to a common position. After reviewing the available scientific evidence, they recently concluded that antibiotics aren’t needed before dental procedures after all.

The national bodies that represent the two professions (the Canadian Orthopaedic Association and the Canadian Dental Association), plus infectious disease specialists (the Association of Medical Microbiology and Infectious Disease Canada) have issued a joint statement calling for an end to the practice.

However, old habits die hard, acknowledges Dr. Tracy Wilson, an orthopedic surgeon at the Thunder Bay Regional Health Sciences Centre and a member of the team that wrote the consensus statement.

“This is a pretty significant change for the orthopedic group,” says Dr. Wilson. “It is going to take a while for us to know whether or not clinicians are actually changing their practice.”

To understand how we got to this point, it’s worthwhile reviewing the long history of this controversy.

Back in 2003, Canadian surgeons and dentists were on the same page. They both followed the example set by their U.S. counterparts who recommended that patients should take a dose of antibiotics one hour before dental procedures for the first two years after they received a knee or hip replacement.

It was hoped that antibiotics would reduce the theoretical risk of germs in the mouth getting into the bloodstream and travelling to the implant and possibly causing an infection.

But “there has never been any evidence” that mouth bacteria were the culprits in these infections, says Dr. Andrew Morris, an infectious disease physician at Mount Sinai Hospital in Toronto, and also a member of the consensus statement team.

Even so, the use of antibiotics seemed justified because the infections – which affect about 1 per cent of knee and hip implant patients – can lead to serious complications. Some patients must have their implants replaced, involving multiple surgeries.

Then in 2009, U.S. orthopedic surgeons called for even stricter infection control measures, saying that joint-implant recipients should use antibiotics before every dental procedure – including routine cleaning – for the rest of their lives.

Meanwhile, Canadian dentists had begun to question antibiotic prophylaxis. They felt that the practice might be doing more harm than good, says Dr. Susan Sutherland, chief of dentistry at Sunnybrook Health Sciences Centre in Toronto, and another consensus statement team member.

Antibiotics, she notes, can wipe out the so-called “good” gut bacteria that help to keep in check “bad” bacteria,such as C. difficile, which can cause severe diarrhea. In some patients, C. difficile can be deadly.

Infectious disease experts also strongly opposed needless antibiotic prophylaxis. They expressed alarm that the misuse of antibiotics is fuelling the emergence of bacterial strains that are resistant to the life-saving medications – creating a threat to public health globally.

Furthermore, new research seemed to exonerate mouth bacteria. Studies revealed that the type of bacteria found in most prosthetic joint infections normally live on the surface of skin – not in the mouth.

Morris speculates that the skin bacteria might enter the body through a cut or may simply get into the joint at the time of the operation – slowly multiplying until an infection becomes apparent. Some joint infections can arise months or years after the surgery.

To further complicate matters, Canadian dentists and surgeons couldn’t agree on who should be responsible for writing the antibiotic prescriptions. Orthopedic surgeons usually see patients for only a few follow-up visits after the operation. That meant the onus fell on the dentists because they have an ongoing relationship with the patients. But the dentists didn’t want to be prescribing an antibiotic which they increasingly felt was unnecessary, says Sutherland.

In order to resolve these differences, experts from the various sides began holding meetings to review the evidence. It was through this process – lasting more than two years – that they agreed antibiotic prophylaxis is generally unnecessary for patients with total joint replacements and those with orthopedic pins, plates and screws.

The consensus statement was approved this past summer, but it is taking time to get the message out to the medical community. So, patients may be still hearing conflicting messages for a while.

“Routine use of antibiotics is not advised,” says Sutherland. “That’s the bottom line.”

Paul Taylor is a patient navigation advisor at Sunnybrook Health Sciences Centre. He is a former Health Editor of The Globe and Mail. You can find him on Twitter @epaultaylor and online at Sunnybrook’s Your Health Matters

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