Do patients with prosthetic joints require dental antimicrobial prophylaxis?
We believe the available evidence does not support routine antimicrobial prophylaxis before dental procedures in patients who have undergone total joint replacement, even though the practice is very common1 and even though professional societies recommend it in patients at high risk,2 or even in all patients.3
On the other hand, good oral hygiene prevents dental disease and decreases the frequency of bacteremia from routine daily activities, and thus should be especially encouraged in patients with prosthetic joints or in those undergoing total joint arthroplasty.
AN UNCOMMON BUT SERIOUS PROBLEM
By 2030, an estimated 4 million total hip or total knee replacements per year will be performed in the United States.4 Most patients have a satisfactory outcome, but in a small percentage the prosthesis fails prematurely.
Prosthetic joint infection is the second most common cause of prosthetic failure leading to loss of joint function, after aseptic loosening.5 Its treatment often requires removal of the infected prosthesis and prolonged intravenous antimicrobial therapy. The cost incurred with each episode of prosthetic joint infection is estimated to exceed $50,000.1
Because of the morbidity and substantial cost associated with managing this condition, investigators have focused on identifying preventable risk factors for it.
RISK FACTORS FOR PROSTHETIC JOINT INFECTION
Factors associated with a higher risk of prosthetic joint infection include prior joint surgery, failure to give antimicrobial prophylaxis during surgery, immunosuppression, perioperative wound complications, a high American Society of Anesthesiologists (ASA) score, prolonged operative time, and a history of prosthetic joint infection.6,7 The primary predisposing factors are related to the foreign body itself and to the opportunities for and the degree of exposure of the prosthesis to microorganisms during surgery. Bacteremia, especially with Staphylococcus aureus, has been recognized as a risk factor for hematogenous prosthetic joint infection.6
Whether dental procedures pose a risk of prosthetic joint infection has been debated for decades. Common daily activities such as toothbrushing and chewing can cause transient bacteremia in up to 40% of episodes.8
Extrapolating from the guidelines for preventing endocarditis, the American Dental Association (ADA)2 and the American Academy of Orthopaedic Surgeons (AAOS)3 have issued guidelines favoring antimicrobial prophylaxis in patients with prosthetic joints. However, given the significant differences in the pathophysiology, microbiology, and anatomy of infection between infective endocarditis and prosthetic joint infection, extrapolating the recommendations may not be valid.
MICROBIOLOGY OF PROSTHETIC JOINT INFECTION AND DENTAL FLORA
Staphylococci, the most common cause of prosthetic joint infection, are uncommon commensals of the oral flora and have been rarely implicated in bacteremia occurring after dental procedures.9 In contrast, viridans-group streptococci constitute most of the facultative oral flora and are the most common cause of transient bacteremia after dental procedures that result in trauma to the gingival or oral mucosa.10 However, viridans-group streptococci account for only 2% of all hematogenous prosthetic joint infections.9
