This week’s blog is a bit more focused and concerns people who have had a hip or knee replacement in the past. If this is not you, this will be quite boring for you. However, if you have had a joint replaced in the past, this information is quite practical and important for you to know.
Prosthetic joint infections occur in approximately 2% of hip and knee replacements. It’s not very common but when it happens it can be a disaster, which in many cases involves many more surgeries and prolonged courses of antibiotics. The failure rate even with all that is in the range of 10-20%.
There are several ways bacteria get into a prosthetic joint. The most common way is at the time of surgery or shortly thereafter where the bacteria get in through the surgical wound. Other less common causes that occur later on are from infection close by like a cellulitis (contiguous spread) that then gets into the joint. Finally, the least common route of infection and the one that gets the most attention is hematogenous spread. This is where bacteria that are swimming in your bloodstream (bacteremia) get deposited into the prosthetic joint. Dental procedures, especially extractions, periodontal procedures, dental implants, and root canals are the ones most likely to cause a transient bacteremia. Well even brushing your teeth causes a little bacteremia activity but its these above mentioned procedures that are notorious for dumping a good serving of bacteria into your bloodstream.
The most important way to prevent prosthetic joint infections is by the administration of an intravenous dose of antibiotic 60 minutes prior to the procedure. This is a well-proven strategy and is essentially standard of care. The other common recommendation has been to give prophylactic antibiotics before dental procedures in hopes of preventing a prosthetic joint infection. This strategy lacks any data to support it and it’s basically expert opinion. Some orthopedic surgeons feel very strongly about using prophylactic antibiotics before bacteremia provoking dental procedures.
In 2003, the American Dental Association (ADA) and the American Academy of Orthopedic Surgeons (AAOS) made a joint statement saying that antibiotic prophylaxis prior to dental procedures is not routinely needed to prevent prosthetic joint infection. Exceptions would be dental procedures with higher risk of bacteremia as stated above or patients with a higher risk of hematogenous joint infection. Examples would be: 1) 2 years or less since joint replacement surgery, 2) immunocompromised patients, and 3) comorbidities such as: prior prosthetic joint infection, malnourishment, hemophilia, HIV, Diabetes, or malignancy.
In 2012, these groups reviewed all the available literature and came out with updated guidelines that are not that different from the older guidelines but they did make things a little more clear I think.
So once again the literature review showed that invasive dental procedures with or without antibiotics do not increase the odds of developing a prosthetic joint infection. Specifically they state: “The available evidence is insufficient to recommend routine antibiotics for dental procedures in persons with joint replacement”. The emphasis here is on the word “routine” because there are a number of notable exceptions:
- Immunocompromised patients: diabetes, autoimmune disease, post-organ transplant, on chemotherapy, bone marrow transplant recipient, HIV positive, on chronic corticosteroids or other immune-modulating agents, obesity, hemophilia, malnutrition, alcoholism, tobacco use, current leukemia or other cancers, history of radiation therapy, and the elderly.
- Oral health status of the patient: current gingivitis, periodontitis, caries, tooth/gum abscess, etc.
- Previous prosthetic joint infection
- Time from joint replacement: There is a higher risk of infection within the first 2 years after joint replacement.
- History of multiple joint replacements.
- At-risk prosthesis: revision prosthesis, prosthesis mechanically failed, megaprosthesis, or endoprosthetic reconstruction.
That’s a lot to remember but I’m sure you will if you are in one of those categories. One consensus opinion between both the ADA and the AAOS is that good oral hygiene is very important if you have a prosthetic joint. It’s good for everyone, obviously, but if you have had a joint replacement it would be a good idea to make friends with a good dentist! Visits at least twice per year are highly recommended.