title: Interleukin-6 and other inflammatory markers in diagnosis of periprosthetic joint infection.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the diagnostic value of interleukin-6 (IL-6) and other inflammatory markers including C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WCC) in diagnosis of PJI.
  
  
  METHODS
  The study group included 40 patients (21 males, 19 females) admitted for surgical intervention after knee or hip arthroplasties. Patients were subjected to careful history taking, thorough clinical examination and pre-operative laboratory investigations including serum IL-6, CRP, WCC and ESR. Peri-implant tissue specimens were subjected to microbiological culture and histopathological examination.
  
  
  RESULTS
  The mean age of patients was 58.4 years (range, 38-72 years). Intra-operative cultures and histopathological examination revealed 11 patients had been infected (PJI) and 29 patients were aseptic failure of prosthesis. Four presumed markers of infection were tested preoperatively: ESR, CRP, WCC, and IL-6. ESR (p = 0.0001), CRP (p = 0.004), WCC (0.0001), and IL-6 (p = 0.0001) were significantly higher in patients with septic revision than those with aseptic failure of the prosthesis. Serum IL-6 (>10.4 pg/ml) reportedly had a sensitivity of 100%, a specificity of 90.9%, a PPV of 79%, a NPV of 100%, and accuracy of 92.5%.
  
  
  CONCLUSIONS
  The present study demonstrated that IL-6 has been found to be the most accurate laboratory marker for diagnosing PJI when compared to ESR, CRP, and WCC. IL-6 above 10.4 pg/ml and CRP level above 18 mg/L will identify all patients with PJI and the combination of CRP + IL-6 is an excellent screening test to identify all such patients (sensitivity 100%, NPV 100%).
authors.affiliation: Orthopaedics and Traumatology, Mansoura School of Medicine, Mansoura, Egypt, elgeidi@doctors.org.uk.
authors.forename: Adham
authors.initials: A
authors.lastname: Elgeidi
authors.forename: Abd Elrahman
authors.initials: AE
authors.lastname: Elganainy
authors.forename: Noha
authors.initials: N
authors.lastname: Abou Elkhier
authors.forename: Shirien
authors.initials: S
authors.lastname: Rakha
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip; D001799:Blood Sedimentation; D002097:C-Reactive Protein / Q000032:analysis; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D007720:Knee Prosthesis / Q000009:adverse effects*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000175:diagnosis*; D012086:Reoperation; D012680:Sensitivity and Specificity
chemical_list: D015850:Interleukin-6; D002097:C-Reactive Protein