CORR Insights®: Are Dental Procedures Associated With Pyogenic Vertebral Osteomyelitis?

Where Are We Now?

During routine follow-up after total joint arthroplasty, patients often ask whether they should be prescribed antibiotics during their regular check-up with the dentist. Often, patients are informed by the experiences of their friends, neighbors, and family members, some of whom underwent total joint arthroplasty before the dissemination of the most-recent recommendations (which recommend against antibiotics for most patients undergoing dental procedures) [1], and some of whom may have been impacted by prosthetic joint infection. Many patients believe that prophylactic antibiotics can prevent these infections, but few patients are aware of the risks of prophylactic antibiotics, such as Clostridium difficile colitis (which is fatal in some patients who develop it and bothersome in all of them), the risk of allergic reactions, and the documented harm of worsening antimicrobial resistance in the general population. Also, and importantly, although there is good evidence that some dental procedures are associated with transient bacteremia, there is no strong evidence that this transient bacteremia causes prosthetic joint infections. In fact, there is strong evidence from a prospective, case-control study that dental procedures are unrelated to subsequent implant infection and that antibiotic prophylaxis before dental procedures does not reduce the infection risk around orthopaedic implants [7].

According to recommendations from the American Academy of Orthopaedic Surgeons and the American Dental Association, these prophylactic antibiotics are not appropriate for most patients [1]. These recommendations are summarized in a decision tree [2] that generally indicates that antibiotics may only be appropriate if the planned dental procedure is invasive (for example, involving gingival manipulation, oral mucosa perforation, or anything around the tip of the root of the tooth) and if the patient is severely immunocompromised (such as patients with inherited immunodeficiency or symptomatic or untreated HIV or AIDS; patients with solid organ transplants who are using immunosuppression therapy; patients with active leukemia, lymphoma, or generalized malignancy or those undergoing certain radiation or chemotherapies; and patients taking high-dose corticosteroids or other immunosuppressive drugs such as disease-modifying antirheumatic drugs, among other conditions), or if the patient has a history of prosthetic joint infection that resulted in surgery to treat it. Prophylactic antibiotics may also be appropriate for patients with poorly controlled diabetes (defined by a hemoglobin A1c level > 8 or random blood glucose level > 199), especially if it has been less than 1 year since surgery [3].

Although an easy-to-use online decision-making tool [4] and a shared decision-making patient handout are readily accessible [8], encounters with concerned patients may result in overtreatment, not unlike the situation in which a doctor prescribes antibiotics for a viral upper respiratory illness. For concerned patients without risk factors, a brief discussion of the guidelines often can assuage their concerns. But if the patient understands the risks of antibiotic treatment and the limited potential benefits, and he or she still feels that prophylactic antibiotics will relieve some of their anxiety, it would be easy to believe that some surgeons may feel compelled to prescribe antibiotics rather than risk harming the doctor-patient relationship.

In this retrospective, comparative study of a claims database designed to replicate a case-crossover design [9], which is published in this issue of Clinical Orthopaedics and Related Research®, the authors isolated patients with hospital-coded pyogenic vertebral osteomyelitis and examined their histories of dental procedures and antibiotic prescriptions. Masuda et al. [9] found that dental procedures were not associated with infection, prophylactic antibiotics did not reduce infection risk, and rather paradoxically, the authors found that patients who were not prescribed antibiotics before dental procedures had substantially lower odds of developing pyogenic vertebral osteomyelitis. Based on these discoveries, surgeons might more carefully examine their own prescribing practices.

Where Do We Need To Go?

Confounding by indication is used to describe a variable that is a risk factor for a disease among nonexposed persons and is associated with the exposure of interest in the population from which conditions derive, without being an intermediate step in the causal pathway between the exposure and the disease [10]. For example, people are more likely to get the flu in the colder winter months, and that’s about the time most people get a flu vaccine booster, but the vaccine does not cause the flu. Without strong evidence to the contrary, and given how often Americans tend to visit their dentists, perhaps dental procedures are not related to prosthetic joint infection at all, and maybe they never were, even in patients with risk factors. Furthermore, for patients with these known risk factors, do prophylactic antibiotics before dental procedures reduce the odds of prosthetic joint infection? Are there any convincing findings or any strong evidence that support that? Or is an orthopaedic surgeon who prescribes prophylactic antibiotics before dental procedures similar to a general practitioner who prescribes antibiotics to treat a viral upper respiratory infection? To arrive at an answer may require unraveling the impact of confounding by indication.

How Do We Get There?

Although prophylactic antibiotics may prevent infection generally, in patients with a high prevalence of risk factors, Masuda et al. [9] found that a claims history of an antibiotic prescription near the time of the proposed inciting event did not change the odds of infection. A similar database study could be performed in a high-risk patient subset who underwent arthroplasty. The prevalence of total joint arthroplasty in the United States is high and increasing, and prosthetic joint infection is becoming the most common reason that these reconstructions undergo revision. Americans also visit their dentists regularly; many visit twice per year. A similar study in patients who underwent arthroplasty could investigate whether the apparent association between dentist visits and prosthetic joint infections is causal or merely coincidental. A retrospective, comparative study with methods similar to that of the current study [9] could shed some light on this topic.

A well-designed retrospective study could overcome other inherent limitations of the authors study. For example, how could the authors determine which of those prescriptions written within 21 days of a dental procedure were actually ingested within 1 hour of the dental procedure? How could they determine the indication for the antibiotic prescription? (Was it prophylactic or was it pneumonia, UTI, or even the flu?) That kind of robust experimental design would not be expected from (and probably could not be achieved by) most retrospective studies. The key may be careful selection of a longitudinal and comprehensive national or continental database that links diagnoses to prescriptions and includes temporal granularity.

But perhaps of greater interest and impact, with even less effort and expenditure, would be a simple survey study to determine what proportion of orthopaedic surgeons regularly prescribe prophylactic antibiotics before dental procedures and how they determine when to do this. A well-designed survey should identify to what extent patient concerns or demands play a role in prescribing patterns and what barriers stand between the current recommendations and patients and their providers. Perhaps the results of such a survey could inform the design of more effective educational materials. If nothing else, a survey study could remind surgeons that these recommendations exist and could help researchers design more effective educational interventions aimed at changing behavior.

Read This Next

The following recommendations are worth reviewing:

• The American Dental Association published guidelines regarding antibiotic prophylaxis before dental procedures [6].

• There are many well-supported recommendations that cover a variety of clinical questions, and OrthoGuidelines [5] is a good tool for accessing them. It links to all the American Association of Orthopaedic Surgeons’ clinical practice guidelines, and is available as a smartphone app.