title: Novel biomarkers to detect infection in revision hip and knee arthroplasties.
abstract: BACKGROUND
  A periprosthetic joint infection is one of the most challenging complications associated with THA and TKA. In the diagnostic process for detecting a periprosthetic joint infection, one of the most important steps is analysis of laboratory infection biomarkers.
  
  
  OBJECTIVE
  We investigated the sensitivity and specificity of the biomarkers procalcitonin, interleukin 6 (IL-6), and interferon α (IFN-α) as compared with conventional biomarkers (C-reactive protein [CRP], leukocyte level) for a periprosthetic joint infection associated with revision arthroplasties.
  
  
  METHODS
  We prospectively included and analyzed 84 patients (124 revision arthroplasties). The blood parameters of interest were procalcitonin, IL-6, IFN-α, leukocyte level, and CRP. Samples were taken preoperatively and on the first, third, and seventh postoperative days. The sensitivity and specificity of these biomarkers then were calculated.
  
  
  RESULTS
  Considering the preoperative values of 84 patients (124 operations), procalcitonin, IL-6, CRP, and leukocyte level correlated with periprosthetic joint infection, whereas IFN-α did not. A procalcitonin cut-off level of 0.35 ng/mL revealed a sensitivity of 80% and specificity of 37%. An IL-6 cut-off level of 2.55 pg/mL had a sensitivity of 92% and specificity of 59%.
  
  
  CONCLUSIONS
  In this study procalcitonin and IL-6 were helpful for detecting periprosthetic joint infections in revision arthroplasties, although CRP generally was superior. Procalcitonin and IL-6 may be considered adjuvant tests when the diagnosis of a periprosthetic joint infection is in doubt. This study showed, in addition to conventional biomarkers such as CRP and leukocyte level, procalcitonin and IL-6 were helpful for detecting infections associated with revision arthroplasties.
authors.affiliation: Department of Orthopaedic Surgery, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria. mathias.glehr@medunigraz.at
authors.forename: Mathias
authors.initials: M
authors.lastname: Glehr
authors.forename: Joerg
authors.initials: J
authors.lastname: Friesenbichler
authors.forename: Günter
authors.initials: G
authors.lastname: Hofmann
authors.forename: Gerwin Alexander
authors.initials: GA
authors.lastname: Bernhardt
authors.forename: Maximilian
authors.initials: M
authors.lastname: Zacherl
authors.forename: Alexander
authors.initials: A
authors.lastname: Avian
authors.forename: Reinhard
authors.initials: R
authors.lastname: Windhager
authors.forename: Andreas
authors.initials: A
authors.lastname: Leithner
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects* / Q000295:instrumentation; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism; D002116:Calcitonin / Q000097:blood; D015740:Calcitonin Gene-Related Peptide; D005260:Female; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D016898:Interferon-alpha / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D007720:Knee Prosthesis / Q000009:adverse effects*; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D011498:Protein Precursors / Q000097:blood; D012086:Reoperation; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D015415:Biomarkers; C000606589:CALCA protein, human; C508600:IL6 protein, human; D018836:Inflammation Mediators; D016898:Interferon-alpha; D015850:Interleukin-6; D011498:Protein Precursors; D002116:Calcitonin; D002097:C-Reactive Protein; D015740:Calcitonin Gene-Related Peptide