Prosthetic Joint Infections: A Welcome 'Guideline'
Perhaps no infection is more disheartening than infected orthopedic hardware. Patients often must proceed through multiple surgeries and prolonged antibiotic therapies for weeks or months. Clinicians, surgeons, and infectious disease consultants have developed customary practices but often feel uneasy, with little robust clinical data to help guide their choices.
I thought it would be worthwhile and quite welcome to discuss the Infectious Diseases Society of America guidelines[1,2] for prosthetic joint infections, which have just been published. I think these are a welcome addition to this area of clinical care. The guidelines have been authored by an international panel of experts who have long labored in the field of musculoskeletal infections. I want to touch on some areas that I found interesting, and perhaps controversial, within the guidelines.
First, I have to say that diagnosis is often a conundrum. Acute infection is rarely a difficult matter, but chronic infection can be something that is only manifest by pain in the joint or perhaps concern for loosening or mechanical failure, and infection only comes to light after joint replacement and swabs or cultures turn up positive after the new joint has been placed.
These chronic or more indolent infections can be quite frustrating, and there is no consensus about the definition of these cases in the guidelines. I think that is for several reasons. First, even the literature is replete with a variety of descriptions and definitions of prosthetic joint infections. Although many people believe that multiple cultures -- [at least] 3 and up to 5 to 6 -- taken at the time of surgery could help provide definitive information, others suggest that diagnosis requires an aspirant of the joint growing a virulent organism such as Staphylococcus aureus.
But for the perplexing cases for which you might call in a skilled histopathologist to perform frozen sections in the operating theater, there is also a difference of opinion as to how to define this. One recent paper by Tsaras,[3] for example, says that some have used 5 or 10 white blood cells per high-powered field [as a definition]. This definition is reasonably helpful to rule in infection, with an odds ratio north of 54, which is quite good, but is less helpful for ruling out infection, with a negative odds ratio of 0.23.
With that in mind, I do think the guideline was perhaps wise to sidestep this area. Indeed, sometimes diagnosis is just in the eyes of the beholder. In numerous situations, a joint has been removed and you may only have 1 or 2 cultures growing out coagulase-negative staphylococci, but the patients had rheumatoid arthritis and now have a new joint in place. What do you do? For that area, I think diagnosis remains controversial, and we have a need for new or better diagnostic methods to help confirm infection.
A fair amount of [the guidelines describe] 1- and 2-stage exchanges as well as revision arthroplasty or arthrodesis and amputation. We are very familiar with many of these, and indeed, in North America, the tendency is towards 2-stage exchanges in appropriate patients, whereas in Europe, the 1-stage exchange is performed perhaps more frequently for total hip arthroplasty.
The choices of antibiotics, again, are not based on any kind of robust data, but typically the guidelines recommend giving antibiotics for 4-6 weeks. One of the more controversial areas in the guideline has to do with the employment of long-term suppression strategies. And here, they provide a range of guidance such that most choices are accommodated in this guideline. For example, the panel split on chronic suppression for both retention of a prosthesis following incision and drainage as well as in 1-stage exchanges, with some giving limited antibiotics, some using long-term suppression, and, in select situations, even using combination therapy with rifampin for staphylococcal infections. Much of this is not based on large amounts of data, and this part of the guideline might be better called a consensus statement, or a "lack of consensus" statement, rather than a guideline.
Last, one of the areas that is often discussed, at least in the ID community, is prophylaxis guidelines, not really for perioperative prophylaxis but more for dental prophylaxis. Orthopedic and dental literature guidelines or statements have existed, yet ID clinicians are often hesitant to follow these recommendations because of scant data. This is sidestepping the guideline, probably because this is such a diverse area with so many different approaches, so many different organisms, such that trying to write this to cover all particular surgical strategies and organisms is extremely difficult. I think the authors did a nice job of trying to pull in as much information as possible, highlight some of the controversies or differences of opinion, and really lead someone reading this to pick their own practice style.
Clearly, there is a need for more information. I doubt that we will ever get large amounts of robust data, at least with current strategies that are recommended by funding agencies. Even for patients willing to participate in a randomized controlled trial of 1-stage vs 2-stage, I think this would be a very difficult trial, but one that, if it could be accomplished, would be wonderful for all of us practicing in this field.
This is a good first step toward a near-comprehensive guideline, and hopefully it can help provide a bit of framework for future areas of research and clinical strategy. Thanks for listening.
References
Osmon DR, Berbari EF, Berendt AR, et al. Executive summary: diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2013;56:1-10. Abstract
Osmon DR, Berbari EF, Berendt AR, et al. Diagnosis and management of prosthetic joint infection: clinical practice guidelines by the Infectious Diseases Society of America. Clin Infect Dis. 2013;56:e1-e25. Abstract
Tsaras G, Maduka-Ezeh A, Inwards CY, et al. Utility of intraoperative frozen section histopathology in the diagnosis of periprosthetic joint infection: a systematic review and meta-analysis. J Bone Joint Surg Am. 2012;94:1700-1711. Abstract
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