January 3, 2011 at 6:30 pm #2964HarrisonKeymaster2 pts
This is an article published in October of 2010 and also pertains to spine patients. Here are my concerns for any patient (with any prosthetic) after revisiting this article:
– These new guidelines fail to employ any understanding of bacterial biofilm infections;
– These new guidelines fail to employ any understanding of the many ways of diagnosing sub-clinical infections;
– These new guidelines fail to employ any understanding of the many ways of treating sub-clinical infections;
– That as a result of not using modern knowledge of bacterial biofilms (from the past 25 years) and new molecular diagnostics (from the past 10 years), patients with infections will suffer in terrible ways.
This is very serious and very bad news. This is further evidence that the standard of care has failed and continues to fail.
Ive heard and read that culture technology may capture up to (and no more than) 5% of all pathogenic bacteria. It will not detect biofilms or bugs in their dormant state, which is what most biofilms are when they become situated on a device or on any human tissue. So why are these guidelines ignoring this important biological fact? This is unconscionable. This quote below says it all:
“…But the fact is that well under 10% of patients present with a fever or obvious signs of infection. Usually they simply have pain…”
When will they start learning about diagnosing and treating chronic infections that are caused by bacterial biofilms?!
Patients: if the diagnostician who you are seeing only understands and subscribes to Kochs postulates, you are in trouble. This is the 170 year-old germ theory that is the basis for our failed standard of care in diagnosing infections. Do some research on Robert Koch and compare that with what has been learned about bacterial biofilms its a new paradigm of understanding bacterial disease. And institutions that need to know this – and practice it dont.
New CPG on diagnosing periprosthetic infections
By Javad Parvizi, MD
Addresses major complication of THA, TKA
At their meeting in June, the AAOS Board of Directors approved a new clinical practice guideline (CPG) on the diagnosis of periprosthetic joint infections. Total joint arthroplasty is an effective means of improving function and decreasing morbidity in patients with degenerative arthritis. However, deep periprosthetic joint infection remains a major complication for both total hip arthroplasty (THA) and total knee arthroplasty (TKA) with an incidence of 1 percent to 2 percent at 2 years postoperatively and up to 7 percent after revision surgery. Infection is a common cause of revision arthroplasty; 15 percent of revision THAs and 25 percent of revisions TKAs are due to infection.
Although the incidence of infection appears to be small, the total number of joint arthroplasties being performed is on the rise. This will undoubtedly lead to a greater number of complex cases, with the presence of multidrug-resistant organisms in sick and immunocompromised patients.
Diagnosis is a challenge
To date, the orthopaedic surgeons biggest challenge has been to correctly diagnose periprosthetic joint infection preoperatively or intraoperatively so that effective treatment regimens capable of eradicating the inciting organism may be implemented. Much effort has gone into optimizing current modalities and creating new ones because no single test can reliably and solely identify such infections.
The preoperative workup for periprosthetic joint infections includes serology with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). These tests have a pivotal role in screening patients at risk, while joint fluid cell count and neutrophil differential have emerged as reliable indicators of infection.
In addition to cell count and differential testing, the aspirated fluid can be cultured for the presence of aerobic and anaerobic organisms. The technetium-Tc99m (99Tc) isotope bone scan, performed alone or combined with Indium-111 radioisotope, and the fluoro-deoxyglucose-positron emission tomography (FDG-PET) have been described in diagnosing periprosthetic joint infections, but with equivocal results.
Intraoperatively, gram staining of periprosthetic tissue samples has demonstrated poor sensitivity in detecting infection. A frozen section of periprosthetic tissue is frequently used to detect acute inflammation and the presence of neutrophils. Currently, the culture of an organism on solid media from multiple specimens obtained during surgery remains the gold standard for diagnosing periprosthetic joint infections. However, culture can fail to correctly identify an inciting organism, even in the presence of overwhelming clinical evidence indicating infection.
To develop the clinical practice guideline, the workgroup first formulated a set of preliminary recommendations that specified what should be done in whom, when, where, how often, or for how long. These were intended to function as the questions for systematic review by the AAOS research team.
Once all relevant published articles were assembled and graded by level of evidence, the workgroup then provided a final recommendation of strong (good quality evidence), moderate (fair quality evidence), weak (poor quality evidence), inconclusive (insufficient or conflicting evidence), or consensus (in the absence of reliable evidence, the workgroup makes a recommendation based on clinical opinion).
The guideline includes 15 recommendations (Table 1). Seven of these are graded as strong, three as moderate, one as weak, one as inconclusive, and three are based on consensus. The work group proposes that patients be stratified into higher or lower probability of infection, based on the following criteria:
[*]Higher probability of infection: One or more symptoms and at least one or more of the following: risk factors (supported by evidence or expert opinion); physical exam finding; early implant loosening/osteolysis (based on radiographic findings)
[*]Lower probability of infection: Pain or joint stiffness only and none of the following: risk factors (supported by evidence or expert opinion); physical exam finding; early implant loosening/osteolysis (based on radiographic findings)
[*]Risk factors identified and supported by the evidence include prior infection of the joint (knee), superficial surgical site infection (hip and knee), obesity (hip), extended operative time (greater than 2.5 hours, hip and knee) and immunosuppression (knee).
Risk factors supported by expert opinion (work group consensus) include recent (within 1 year) bacteremia or candidemia findings; metachronous prosthetic joint infection; skin disorders (psoriasis, chronic cellulitis, lymphedema, chronic venous stasis, skin ulcers); intravenous drug use; recent (within 3 years) infection or colonization with methicillin-resistantStaphylococcus aureus; active infection at another site.
In addition, the work group developed several algorithms illustrating the recommendations of the guidelines. Readers are encouraged to refer to these algorithms when reading the guideline, which is available atwww.aaos.org/guidelines
Javad Parvezi, MD, served as vice chair of the workgroup that developed the clinical practice guidelines on the diagnosis of periprosthetic joint infections.
How the guidelines came to be
The Clinical Practice Guideline on the Diagnosis of Periprosthetic Joint Infections, adopted by the AAOS Board of Directors at their June 2010 meeting, was developed by a multidisciplinary volunteer work group that included orthopaedic surgeons who practice in a variety of settings, along with assistance from the AAOS guidelines unit. They included Craig Della Valle, MD, chair; Javad Parvizi, MD, FRCS, vice-chair; Thomas W. Bauer, MD, PhD; Paul E. DiCesare, MD; Richard Parker Evans, MD; John Segreti, MD; Mark Spangehl, MD; William C. Watters III, MD; Michael Keith, MD; Charles M. Turkelson, PhD; Janet L. Wies, MPH; Patrick Sluka, MPH; and Kristin Hitchcock. Special acknowledgement goes to research analysts Sara Anderson, MPH; Kevin Boyer; and Laura Raymond, MA.
Among the groups that participated in peer review of this guideline were the American Association of Hip and Knee Surgeons, the European Bone and Joint Infection Society, the Knee Society, the Musculoskeletal Infection Society, and the Society of Nuclear Medicine.
Funding was provided solely by the AAOS.
The guideline is based on a systematic review of the current scientific and clinical information on accepted approaches to treatment and/or diagnosis. The entire process included a review panel of internal and external committees, public commentaries, and final approval by the AAOS Board of Directors on June 18, 2010.
The methods used to prepare this guideline were rigorous, employed to minimize bias and to develop a set of reliable, transparent, and accurate clinical recommendations for diagnosing periprosthetic joint infections. These methods are detailed in the full guideline.
The development of AAOS evidence-based clinical practice guidelines is overseen by the Guidelines and Technology Oversight Committee and the Evidence-Based Practice Committee. The guideline is available atwww.aaos.org/guidelines
AAOS issues clinical guidelines for diagnosing hip, knee periprosthetic joint infections
Robert L. Barrack
When diagnosing periprosthetic joint infections of the hip and knee, practitioners should begin with a simple blood test and withhold antibiotics until after obtaining culture results, according to new practice guidelines released by the American Academy of Orthopaedic Surgeons.
Among the 15 evidence-based recommendations included in the American Academy of Orthopaedic Surgeons (AAOS) guidelines are that joint aspirations should vary depending on the location of the arthroplasty, either hip or knee, and that probability of infection be based on established risk factors, including patient history.
I would say these guidelines are long overdue and will be helpful, said Robert L. Barrack, MD, a professor of orthopedics at Washington University School of Medicine in St. Louis. For example, for well over 10 years now, there have been problems accurately diagnosing knee aspiration because such a high percentage of our patients have been placed on antibiotics. In short, you want to make an accurate diagnosis as quickly as possible.
One of the challenges of diagnosing infected total joints is that most of the time they are low grade and insidious. Patients just present with unexplained pain, Barrack told Orthopedics Today. Most people think that if you have an infection deep in your hip or knee, it will be accompanied by fever, chills and other classic signs of infection. But the fact is that well under 10% of patients present with a fever or obvious signs of infection. Usually they simply have pain.
As the guidelines recommend, Barrack routinely performs a blood test for erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), for which the chance of infection is low when both ESR and CRP are normal.
Furthermore, for patients being evaluated for periprosthetic joint infections in preparation for revision surgery, multiple cultures should be obtained. A single culture can be misleading because when you take fluid or tissue from a joint and send it to the laboratory, there are several steps along the way during which the specimen can become contaminated from the back table of the operating room to in the lab itself. Bacteria can fall from the air or from the technician handling the tissue, Barrack said. Contamination probably occurs more than 10% of the time. Therefore, the best thing to do is collect four or five cultures.
Securing frozen sections of tissues adjacent to the implant, when infection has not already been established or excluded, is also important. This is a helpful tool, although not 100% accurate, Barrack said. We found that taking antibiotics can suppress growth on culture media for even longer than 6 weeks. And in about 5% of cases, you never do grow anything. Most often it is because people have been on antibiotics.
Barrack also found that gram stains are not nearly as accurate for diagnosis as previously thought.
Craig J. Della Valle, MD, an associate professor of orthopedic surgery at Rush University Medical Center in Chicago, was chair of the physician work group that developed the guidelines. In an AAOS press release, he underscored the importance of delaying antibiotics. The first rule of treatment in medicine is always to make the diagnosis first, Della Valle stated. Unfortunately, we often see patients who are given antibiotics prior to having appropriate cultures drawn from within the joint that can lead to a delay in diagnosis and a subsequent delay in appropriate treatment.
Further, identification of the specific bacteria which is causing the infection is important in administering the most effective antibiotic to cure the infection. If antibiotics are given before we can get a good culture, we may not have the advantage of knowing exactly which antibiotics to give as the cultures can turn negative even after a single dose of antibiotics.
Because any single orthopedic surgeon is unlikely to encounter many cases of periprosthetic joint infections, it is probably easier to treat with a team of specialists, including a total joint specialist, an infectious disease specialist and a plastic surgeon, Barrack said. by Bob Kronemyer
Robert L. Barrack, MD, can be reached at Washington University School of Medicine, 660 S. Euclid Ave., Campus Box 8233, Department of Orthopedic Surgery, St. Louis, MO
Craig J. Della Valle, MD, can be reached in the Department of Orthopaedic Surgery, Rush University Medical Center, 1725 West Harrison, Suite 1063, Chicago, IL
The recently released guidelines from the AAOS on diagnosis of periprosthetic joint infection (PJI) is the result of many months of work by the AAOS staff and volunteer experts who evaluate all relevant literature pertinent to the topic and devise guidelines based on available evidence. These guidelines are extremely important and timely. The incidence of PJI is on the rise and this dreaded complication poses a real challenge to the orthopedic community. In addition, there is emerging evidence that some of the so called aseptic failures are indeed infections that have escaped the available diagnostic modalities for PJI.
The AAOS workgroup under the leadership of Craig Della Valle, MD, has put together practical and step-by-step guidelines that, in my opinion, will lead to better patient care and reduced cost. The members of the AAOS staff and the volunteer experts should be congratulated for producing one of the most critical and relevant guidelines for the fellowship and the other physicians engaged in the care for patients with failed arthroplasty.
Javad Parvizi, MD, FRCS
Member of the AAOS physician work group
Editor, Orthopedics Today Infection Watch column
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