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AAOS Systematic Literature Review

Summary on the Management of Surgical Site Infections

McLaren, Alexander C. MD; Lundy, Douglas W. MD, MBA

JAAOS - Journal of the American Academy of Orthopaedic Surgeons: August 15, 2019 - Volume 27 - Issue 16 - p e717–e720
doi: 10.5435/JAAOS-D-18-00653
AAOS Clinical Practice Guideline Summary
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The purpose of this systematic review is to improve outcomes for the care of surgical site infections by presenting the current best evidence on important diagnostic and care issues. The findings led to ten recommendations and five consensus statements that address diagnosis and treatment of orthopaedic surgical site infections. There is strong evidence to supports anemia, obesity, HIV/AIDS, depression, dementia, immunosuppressive medications, duration of hospital stay, history of alcohol abuse, and history of congestive heart failure as factors that increased the risk of infection, some of which are modifiable before surgical intervention. Diagnostically, synovial fluid and tissue cultures were found to be strong “rule-in” tests for the diagnosis of infection, but negative synovial fluid and tissue cultures do not reliably exclude infection. C-reactive protein was found to be a strong rule-in and rule-out marker for patients with suspected surgical site infections. Therapeutically, only for patients with retained implants, antimicrobial protocols of 8 weeks of duration were found to be associated with outcomes that are not inferior to outcomes from protocols of 3- to 6-month duration. Also only for patients with retained implants, rifampin, used as a second antimicrobial, increases the probability of treatment success for staphylococcal infections. The surgical site infection work group identified a lack of high-level outcomes data, highlighting the need for high-quality clinical trials in the treatment of surgical site infections.

From Orthopaedic Surgery, University of Arizona, College of Medicine-Phoenix, Phoenix, AZ (Dr. McLaren), and Resurgens Orthopaedics, Atlanta, GA (Dr. Lundy).

Dr. McLaren or an immediate family member has stock or stock options held in Sonoran Biosciences; and serves as a board member, owner, officer, or committee member of American Academy of Orthopaedic Surgeons, American Board of Orthopaedic Surgery, and Musculoskeletal Infection Society. Dr. Lundy or an immediate family member is a member of a speakers' bureau or has made paid presentations on behalf of Synthes; and serves as a board member, owner, officer, or committee member of American Academy of Orthopaedic Surgeons, American Board of Orthopaedic Surgery, American Orthopaedic Association, and Orthopaedic Trauma Association.

Management of Surgical Site Infections from the American Academy of Orthopaedic Surgeons, Rosemont, IL.

This systematic review was approved by the American Academy of Orthopaedic Surgeons on June 9, 2018. The complete Systematic Literature Review on the Management of Surgical Site Infections including all tables, figures, and appendices is available at aaos.org/cpg/.

Management of Surgical Site Infections Systematic Review Panel: Douglas W. Lundy, MD, MBA; Alex C. McLaren, MD; Paul A. Anderson, MD; Hrayr G. Basmajian, MD; Kim J. Chillag, MD; Thomas B. Fleeter, MD; Sudheer C. Reddy, MD; Gregory S. Stacy, MD; Sandra Bliss Nelson, MD; Gwo-Chin Lee, MD; Joseph R. Hsu, MD; Peter F. Sturm, MD; Non-Voting: Carter Cassidy, MD. Staff of the American Academy of Orthopaedic Surgeons: William O. Shaffer, MD; Deborah Cummins, PhD; Jayson Murray, MA; Danielle Schulte, MS; Mukarram Mohiuddin, MPH; Mary DeMars; Kaitlyn Sevarino, MBA; Peter Shores, MPH; Anne Woznica, MLIS, AHIP.

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Rationale

The systematic review (SR) titled Systematic Literature Review on the Management of Surgical Site Infections (MSSI-SR)1 was recently (June 2018) published by the American Academy of Orthopaedic Surgeons (AAOS), with inputs from the Musculoskeletal Infection Society (MSIS), the Infectious Diseases Society of America (IDSA), the American College of Radiology (ACR), the Orthopaedic Trauma Association (OTA), the Pediatric Orthopaedic Society of North America (POSNA), the Knee Society, the Arthroscopic Association of North America (AANA), and the American Orthopaedic Society of Sports Medicine (AOSSM).1 The goal was to provide health-care professionals with an up-to-date summary and analysis of all credible evidence related to the management of surgical site infection (SSI), as of June 2017, coinciding with the Center for Disease Control and Prevention’s preparation to update their 1999 Guideline for Prevention of Surgical Site Infection. The AAOS workgroup on MSSI-SR (MSSI-WG) used the processes and language from the AAOS Clinical Practice Guidelines and Systematic Review Methodology2 under oversight of the AAOS Committee on Evidence-Based Quality and Value.3 The methodology, updated in 2013, aims to minimize bias and enhance transparency in the selection, appraisal, and analysis of the available evidence for each outcome. Six carefully worded PICO-T questions4 (patient/population, intervention, comparison, outcome and time) covering current clinically relevant issues including modifiable risk factors, diagnostic modalities, antimicrobial therapy, role and timing of treatment modalities (débridement, implant removal, percutaneous drainage), adjunctive treatments and multidiscipline care (eAppendix 1)2 were developed by the MSSI-WG and used to determine and expand search criteria following the AAOS research quality designations.2 The “best-available evidence synthesis,” was used for analysis.2 Although all studies that meet the inclusion criteria were examined, only those with the highest levels of evidence were used in the analysis, leading to recommendations with a corresponding validity rating (Strong, Moderate, Limited).2 Consensus statements based on expert opinion were made when there was no available empirical evidence that met the inclusion criteria for the SR.

Through a comprehensive search of PubMed, Embase, and the Cochrane Central Register of Controlled Trials from 1966 to 2017, 10,804 English language citations were identified. The search terms can be found in eAppendix 1.3 The abstracts were reviewed for sample size (≥10 per study group) to limit the “small study” effect of low-power clinical trials and to help mitigate publication bias. Follow-up of at least 3 months for surgical care and 1 month for nonsurgical care was required. Data were abstracted and analyzed from full-text manuscripts of 230 high-quality peer-reviewed publications.

Peer review and specialty society comment is important for the process of evidence synthesis and formulation of recommendations. When completed, the MSSI-SR and the resultant recommendations were subjected to peer review by seven independent reviewers that were recommended by POSNA, ACR, AANA, OTA, AAHKS, MSIS, or APTA (American Physical Therapy Association).5 Following approval by the Evidence-Based Quality and Value and CORQ committees and the AAOS Board of Directors, the MSSI-SR was sent to the stakeholder societies for their comments.3 MSIS, OTA, POSA, and AANA have all endorsed the MSSI-SR and the recommendations that were derived from evidence found in the SR.

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Overview

The full-text version of recommendations that were based on the findings of the MSSI-SR with the rationale and all the citations can be found at www.orthoguidelines.org/topic?id=1022.12 The MSSI-WG is aware that clinical recommendations can be misapplied. The recommendations that follow this SR are intended to help guide medical care in relevant clinical scenarios, and not for the determination of payment for care. It is cautioned that thoughtful attention to an individual patient's presentation is needed to determine when the recommendations are applicable and when they are not. Attention is drawn to two of the recommendations: recommendation # 1 (attributes of clinical specimens and culture methodology to optimized culture yield) and recommendation # 9 (indications for use of rifampin as a second agent to treat staphylococcal infections with retained implants). These recommendations are expected to have an important impact on patient care based on the MSSI-WG perception that current care delivery is often not consistent with the supporting data and that the expected improvement in outcomes is considerably greater than the minimum clinically important improvement (MCII).6 The other recommendations, while valid, are not expected to have as large an impact on clinical practice because they are either generally well understood and followed to a large degree (eg, CRP) or their effect on outcomes is not as well understood (eg, modifiable risk factors). Although there are inherent faults in using the MCII to determine clinical importance, as opposed to statistical significance, the AAOS uses MCII as a metric in their SR process as a validated measure of importance when trying to determine whether an intervention is truly effective, not just a numerically distinct outcomes data set.7-10 The MSSI-WG also draws attention to the critical need for high-quality studies to identify effective modalities to manage biofilm and immune response, optimize antimicrobial regimens, and mitigate risk factors to effect improved outcomes for the management of SSI. SRs provide supporting evidence for diagnostic tests and care interventions. To add perspective and context, Case Studies and Appropriate Use Criteria will follow. Both Case Studies and AUCs illustrate patient scenarios where recommendations can be applied appropriately.

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Recommendations

There are ten recommendations. Additionally, in response to five problems (P) where interventions (I) had no supporting evidence but the possible outcomes (O) could lead to severe morbidity or death, the MSSI-WG was able to reach consensus. The five consensus statements can be found in the document “SSI Companion Consensus Statements.”11 A nuanced discussion of data used to develop each recommendation and all citations for the evidence that supports each recommendation are available in the full guideline at www.orthoguidelines.org/topic?id=1022.12 Readers are referred to the full guideline for the source of and context for these important details. The findings and recommendations from the MSSI-SR cannot be implemented independently. Medical decision making is a joint process between the provider and the patient taking into account the provider's experience and capabilities and the patient’s individual needs and expectations, in addition to the best available knowledge.13

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Medical Imaging

Limited evidence supports the use of medical imaging in the diagnostic evaluation of patients with a suspected organ/space (ie, bone, joint, and implant) surgical site infection.

Strength of Recommendation: Limited.

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Cultures

Strong evidence supports that synovial fluid and tissue cultures are strong rule-in tests for the diagnosis of infection; negative synovial fluid and tissue cultures do not reliably exclude infection.

Strength of Recommendation: Strong.

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C-Reactive Protein

Strong evidence supports that C-reactive protein is a strong rule-in and rule-out marker for patients with suspected surgical site infections.

Strength of Recommendation: Strong.

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Erythrocyte Sedimentation Rate

Limited strength evidence does not support the use of erythrocyte sedimentation rate (ESR), alone, to rule in or rule out surgical site infections because of conflicting data.

Strength of Recommendation: Limited.

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Clinical Examination for the Diagnosis of Surgical Site Infections

Moderate strength evidence supports that clinical examination (ie, pain, drainage, fever) is a moderate to strong rule-in test (ie, high probability of presence of infection if the test is positive) for patients with suspected surgical site infections, but a weak rule-out test.

Strength of Recommendation: Moderate.

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Strong Evidence of Factors Associated With Increased Risk of SSI

Strong evidence supports that the following factors are associated with an increased risk of infection:

  • (1) Anemia
  • (2) Duration of hospital stay
  • (3) Immunosuppressive medications
  • (4) History of alcohol abuse
  • (5) Obesity
  • (6) Depression
  • (7) History of congestive heart failure
  • (8) Dementia
  • (9) HIV/AIDS

Strength of Recommendation: Strong.

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Moderate Evidence of Increased Associated SSI Risk

Moderate strength evidence supports that patients meeting one or more of the following criteria are at an increased risk of infection after hip and knee arthroplasty.

  • (1) Chronic kidney disease
  • (2) Diabetes (conflicting evidence)
  • (3) Tobacco use/smoking (conflicting evidence)
  • (4) Malnutrition (conflicting evidence)

Strength of Recommendation: Moderate.

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Limited Evidence of Increased Associated SSI Risk

Limited strength evidence supports that patients meeting one or more of the following criteria are at an increased risk of infection after hip and knee arthroplasty:

  • (1) Cancer
  • (2) Hypertension (conflicting evidence)
  • (3) Liver Disease (conflicting evidence)

Strength of Recommendation: Limited.

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Antibiotic Duration for Management of Surgical Site Infections

Moderate evidence supports that in the setting of retained total joint arthroplasty, antibiotic protocols of 8 weeks do not result in significantly different outcomes when compared with protocols of 3- to 6-month duration.

Strength of Recommendation: Moderate.

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Rifampin Use for Management of Surgical Site Infections

Moderate evidence supports that rifampin, as a second antimicrobial, increases the probability of treatment success for staphylococcal infections in the setting of retained orthopaedic implants.

Strength of Recommendation: Moderate.

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References

References printed in bold type are those published within the past 5 years.

1. American Academy of Orthopaedic Surgeons: Systematic Literature Review on the Management of Surgical Site Infections. https://www.aaos.org/uploadedFiles/PreProduction/Quality/Guidelines_and_Reviews/ssi-sr-09132018.pdf. Accessed September 21, 2018.
2. American Academy of Orthopaedic Surgeons: Clinical Practice Guideline and Systematic Review Methodology. https://www.aaos.org/uploadedFiles/PreProduction/Quality/Guidelines_and_Reviews/Guideline%20and%20Systematic%20Review%20Processes_v4.0_Final.pdf. Accessed September 21, 2018.
3. American Academy of Orthopaedic Surgeons: Systematic literature review on the management of surgical site infections, 2018—background, work group roster, PICO questions, AAOS approval bodies, literature search strategies, peer review/public comment details eAppendix 1. file:///C:/Tools/Download%20Folder/SSI%20SR%20eAppendix%201%209.13.18%20(12).pdf. Accessed September 21, 2018.
4. Schardt C, Adams MB, Owens T, Keitz S, Fontelo P: Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Making 2007;7:16.
5. American Academy of Orthopaedic Surgeons: Peer review and public commentary report on the systematic literature review on the management of surgical site infections. https://www.aaos.org/uploadedFiles/PreProduction/Quality/Guidelines_and_Reviews/SSI%20CPG%20Peer%20Review%20Report%206.20.18.pdf. Accessed September 21, 2018.
6. Jevsevar DS: The importance of clinical significance in AAOS CPGs. AAOS Now 2013. http://www.aaos.org/news/aaosnow/may13/research2.asp. Accessed December 12, 2018.
7. Angst F, Aeschlimann A, Michel BA, Stucki G: Minimal clinically important rehabilitation effects in patients with osteoarthritis of the lower extremities. J Rheumatol 2002;29:131–138.
8. Angst F, Aeschlimann A, Stucki G: Smallest detectable and minimal clinically important differences of rehabilitation intervention with their implications for required sample sizes using WOMAC and SF-36 quality of life measurement instruments in patients with osteoarthritis of the lower extremities. Arthritis Rheum 2001;45:384–391.
9. Guyatt GH, Juniper EF, Walter SD, Griffith LE, Goldstein RS: Interpreting treatment effects in randomized trials. BMJ 1998;316:690–693.
10. Tubach F, Wells GA, Ravaud P, Dougados M: Minimal clinically important difference, low disease activity state, and patient acceptable symptom state: Methodological issues. J Rheumatol 2005;32:2025–2029.
11. American Academy of Orthopaedic Surgeons: Management of surgical site infections companion consensus statements. http://www.aaos.org/ssiconsensus. Accessed September 21, 2018.
12. American Academy of Orthopaedic Surgeons: OrthoGuidelines. 2018. http://www.orthoguidelines.org/topic?id=1022. Accessed December 12, 2018.
13. Straus SE, Glasziou P, Richardson WS, Haynes RB: Evidence-Based Medicine: How to Practice and Teach It, ed 4. Edinburgh, United Kingdom, Churchill Livingstone Elsevier, 2011.
© 2019 by American Academy of Orthopaedic Surgeons