Patients who have received a a prosthetic joint replacement (artificial knee, hip, etc.) are often confused by conflicting recommendations from their orthopedic surgeons and dentists regarding the need for antibiotic premedication prior to dental procedures. Years of research and debate have resulted in the latest guidelines from a joint commission of the American Academy of Orthopedic Surgeons (AAOS) and the American Dental Association (ADA). The latest guidelines represent the culmination of 25 years of research and are the sixth joint information statement issued by the AAOS and ADA regarding the most current understanding of prosthetic joint infections and antibiotic premedication regimens. The pendulum has swung widely over the decades from previous recommendations for pre- and post-op antibiotic administration, to current guidelines that practically eliminate the use of antibiotic premed except in rare circumstances.

A dentist's first priority in proceeding with any treatment recommendation, including the prescription of antibiotics, should be to "do no harm", and there are several reasons not to routinely prescribe antibiotic premedication for patients with prosthetic joint replacements. The first fundamental finding of research was that 95% of all prosthetic joint infections are caused by staphylococcal bacteria, not oral streptococcal viridans. These organisms do not arise  from oral sources, but from bacterial infections occurring at the time of orthopedic surgery, or staph skin infections and subsequent blood infections. The transient streptococcal bacteremia that occurs after a dental procedure is minimal compared to the bacteremia occurring from everyday chewing, brushing, and flossing of the teeth.

In addition, research has revealed that antibiotic premedication does not eliminate the transient bacteremia from dental procedures. A dose of 2 grams of Amoxicillin only reduced bacteremia by 50%, while Clindamycin (given as an alternative to Amoxicillin-allergic patients) was completely ineffective at reducing bacteremia, and no better than a placebo. This changed the risk/benefit profile of antibiotic regimens for the prevention of prosthetic joint infections. Now the emphasis is placed on protecting patients from the potential adverse effects of prescribing antibiotics when not necessary. Risks associated with taking unneeded antibiotics include allergic reactions, anaphylaxis, GI disturbances, the development of antibiotic-resistant bacteria, and secondary infection with Clostridioides difficile (C. diff). Antibiotic-resistant infections result in 35,000 fatalities each year in the United States, and an additional 29,000 deaths from C. diff infections. The majority of these C. diff infections are attributed to antibiotic use, so any unnecessary prescriptions for antibiotics contribute to those fatalities. Unfortunately, the major risk factors for these infections are recent antibiotic use, recent hospitalization, and patient age over 65 years; which affect the majority of prosthetic joint patients.

The greater the number of courses of antibiotic treatment a patient receives, the greater their chance of having an adverse, or even life threatening reaction. Taking into consideration the average number of dental procedures undergone by patients each year (for a lifetime), reducing the number of antibiotic regimens prescribed is of paramount importance. The AAOS and ADA currently recommend antibiotic premedication in cases of prosthetic joint replacement, only when the following co-morbidities occur together: immunocompromise, diabetes, and a history of prior joint infections. That is an extremely limited number of patients, and the latest guidelines from the AAOS and ADA indicate that "In general, for patients with prosthetic joint implants, prophylactic antibiotics are not recommended before dental procedures to prevent prosthetic joint infection."

With one million knee and hip replacements being performed each year in the United States, dental offices will see patients with prosthetic joints regularly. Dentists need to fully inform their patients about the inherent risks of antibiotic premed, and not prescribe it when the risks outweigh the benefits. Dentists should encourage their patients to have frank discussions with their orthopedic surgeons if they continue to prescribe antibiotic premed prior to dental procedures. Dentists should continue to be well informed regarding the risks of antibiotic prophylaxis and protect the long term health of their patients.