title: EKA survey: diagnosis of prosthetic knee joint infection.
abstract: OBJECTIVE
  Due to the juvenility of research in the field of periprosthetic joint infection (PJI), approaches employed for diagnosis of PJI vary amongst surgeons in different geographic regions. The aim of this study was to determine common diagnostic approaches utilized by European knee arthroplasty surgeons for the diagnosis of PJI.
  
  
  METHODS
  A task force was established for questionnaire development, consisting of surgeons and clinical researchers who each had a record of publishing in the field of PJI. A pool of items was initially generated from a Medline literature search. These were organized into a file and independently sent to each task force member for evaluation and additional supplementation. After reaching a consensus, a final online version was generated and administered to all 4865 members of the "European Society of Sports Traumatology Knee Surgery & Arthroscopy".
  
  
  RESULTS
  There were 262 respondents between August 2015 and March 2016. Most European surgeons (41.1 %) diagnose between 2 and 5 PJIs yearly, and only 5.8 % diagnose >30 PJIs per year. Serum tests to rule out infection were commonly CRP (97.7 %), leucocyte count (73.6 %) and microbiology cultures (45.3 %), while serum interleukins were least common (<5 %). Synovial fluid exams most commonly included microbiology (97.7 %), leucocyte count (74.8 %), percentage polymorphonuclear cells (65.8 %), synovial fluid CRP (26.4 %) and α-defensin (19.4 %). Conventional radiographs represent the most common radiographic exam (87.6 %) followed by SPECT-CT scans (41.7 %). The majority (93.6 %) take biopsies at the time of surgery, 62.0 % take 1-5 biopsies, and 34.9 % take >5. Most biopsies (98.8 %) are sent for culture exams and 72.5 % for histology, and 36.4 % of surgeons send the implants for sonication.
  
  
  CONCLUSIONS
  Microbiology and cell count remain the most commonly applied synovial fluid tests in Europe, while α-defensin and leucocyte esterase are currently less common. Serum interleukins have not gained widespread use. Implant sonication, despite evidence of diagnostic effectiveness, was only applied by one-third of survey respondents, highlighting the problematic issues of cost and accessibility of some tools. The results highlight the current state of European diagnostic practice, emphasizing the areas of divergence from state of evidence and demonstrating the need for development of standard diagnostic algorithms.
  
  
  METHODS
  Cross-sectional survey, Level IV.
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Freiburgstrasse, Bern, Switzerland. Sufian.ahmad@insel.ch.
authors.forename: Sufian S
authors.initials: SS
authors.lastname: Ahmad
authors.affiliation: Department of Orthopedics and Traumatology, Centre of Joint Replacement, Hospital Brandenburg, Medical School "Theodor Fontane", Hochstrasse 2, 14770, Brandenburg/Havel, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Becker
authors.affiliation: Rothman Institute, Thomas Jefferson University Hospital, Philadelphia, PA, USA.
authors.forename: Antonia F
authors.initials: AF
authors.lastname: Chen
authors.affiliation: Department of Orthopaedic Surgery and Traumatology, Inselspital, University of Bern, Freiburgstrasse, Bern, Switzerland.
authors.forename: Sandro
authors.initials: S
authors.lastname: Kohl
mesh_terms: D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D001706:Biopsy / Q000706:statistics & numerical data; D001799:Blood Sedimentation; D002097:C-Reactive Protein; D003430:Cross-Sectional Studies; D003952:Diagnostic Imaging / Q000706:statistics & numerical data; D005060:Europe; D006801:Humans; D007958:Leukocyte Count; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data*; D016459:Prosthesis-Related Infections / Q000175:diagnosis*; D011795:Surveys and Questionnaires; D013582:Synovial Fluid / Q000382:microbiology
chemical_list: D002097:C-Reactive Protein
keywords: Diagnosis; Diagnostic; Knee infection; Knee replacement; PJI; Prosthetic joint infection; TKA