title: Synovial IL-6 as inflammatory marker in periprosthetic joint infections.
abstract: We analyzed serum and synovial biomarkers of 69 patients. 31 of them suffered from a periprosthetic joint infection (PJI) and 38 from aseptic arthralgia after total joint arthroplasty. We used Receiver-Operating-Characteristic-curves to calculate the Area-under-the-curve (AUC), cutoff-values, positive (+LR), negative (-LR) and interval-Likelihood-Ratios (iLR) for predicting a PJI. The most significant parameter was synovial interleukin-6 (IL-6) (cutoff-value ≥ 30,750 pg/ml, AUC = 0.959, SE = 90.0%, SP = 94.7%, +LR = 17.27), followed by synovial lactate (cutoff-value ≥ 8.3 mmol/l, AUC = 0.844, SE = 71.4%, SP=88.0%, +LR = 5.95), and synovial glucose (cutoff-value ≤ 44 mg/dl, AUC = 0.829, SE = 79.2%, SP = 78.6%, +LR = 3.69). IL-6 ≥ 30,750 pg/ml and lactate ≥ 10 mmol/l make a PJI very likely, IL-6 <10,000pg/ml or lactate <4.3 mmol/l makes a PJI very unlikely. If none of these thresholds are met, physicians should use the iLR of IL-6, glucose and lactate to estimate the likelihood of PJI.
authors.affiliation: Department of Orthopedics and Trauma Surgery, Klinikum Dachau, Academic Teaching Hospital of the Ludwig-Maximilians-University of Munich, 7 Krankenhausstraße 15, 85221 Dachau, Germany; Faculty of Medicine, Technical University of Munich, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Lenski
authors.affiliation: Department of Orthopedics and Trauma Surgery, Klinikum Dachau, Academic Teaching Hospital of the Ludwig-Maximilians-University of Munich, 7 Krankenhausstraße 15, 85221 Dachau, Germany.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Scherer
mesh_terms: D019643:Arthroplasty, Replacement / Q000009:adverse effects; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D006801:Humans; D015850:Interleukin-6 / Q000032:analysis* / Q000097:blood; D016459:Prosthesis-Related Infections / Q000097:blood / Q000175:diagnosis* / Q000382:microbiology; D013582:Synovial Fluid / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D015850:Interleukin-6
keywords: inflammatory marker; interleukin-6; lactate; periprosthetic joint infection; synovial fluid; synovial fluid white blood cell count