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In an update 12 years in the making, two orthopedic surgeons' organizations have issued new guidance on preventing periprosthetic joint infections (PJIs) when patients undergo dental procedures before or after hip and knee replacements.

Dental procedures other than the most benign (such as x-rays) should wait 3 months after an arthroplasty, according to by the American Academy of Orthopaedic Surgeons (AAOS) and American Association of Hip and Knee Surgeons (AAHKS).

But there's little evidence that giving systemic antibiotics prior to dental work reduces PJI risk, the groups determined.

"The committee took a close look at the data on the administration of antibiotics before a dental procedure after both hip and knee replacement to see if it mitigated the potential risk of a PJI associated with that dental procedure," said Charles Hannon, MD, co-chair of the AAOS' guideline development group, in a press release.

"With that said," he added, "it is important to recognize there may be other considerations that may lead a provider to prescribe antibiotics for an individual patient. This decision should be made with the patient, and the unique risks and benefits for the patient should be considered."

Also in the update is a caution that screening patients for dental problems prior to undergoing total hip or knee replacement may not reduce PJI risk either.

Notably, both of these statements were denoted as "limited" and based on low-quality evidence.

The new guideline also includes two recommendations in which the authors had more confidence, despite having no solid evidence, but rather was based on "expert opinion." These were:

• Joint replacements can proceed even just 1 day after a non- or minimally invasive dental procedure.
• But procedures that involve more tissue penetration, from gingival probing to extractions and other oral surgeries, should wait at least 3 months after arthroplasty.

In both situations, the issue is the potential duration of bacteremia following dental work. "Non-invasive dental procedures which induce bacteremia do so transiently, with pathogen clearance occurring within hours, or at the longest, within a day following the procedure," the committee wrote. But when oral tissue barriers are breached, more bacteria can enter circulation; even though the resulting bacteremia may be transient, it "could potentially seed the newly placed highly perfused joint replacement."

"For [this] concern, indirect clinical evidence and animal studies suggest that the surgical site may have increased hematogenous seeding risk for up to 3 months postoperatively," the authors explained.

It's possible that certain types of invasive procedures might be OK to perform in less than 3 months, the committee acknowledged, but data are insufficient to reach firm conclusions. For one thing, individual patients' immunocompetence is an important factor in how long bacteremia may persist. Therefore, the committee decided to play it safe and set the 3-month delay as a blanket recommendation for all but the least invasive procedures.

The guideline also addressed dental-related reasons to delay arthroplasty, e.g., when patients have had very invasive procedures including extractions and root canals. In these cases, surgeons should schedule hip or knee replacements at least 3 weeks after such procedures. As well, when patients have dental infections, arthroplasty should not occur until 3 weeks after the active infection has resolved.

On the other hand, minimally invasive procedures including scaling and root planing, either manual or ultrasonic, require only a 1-week wait before arthroplasty can proceed.

Not surprisingly, the AAOS and AAHKS called for more research into all these questions in order to refine the recommendations in future updates.

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