Diagnostic accuracy of synovial fluid, blood markers, and microbiological testing in chronic knee prosthetic infections

• Published in: Archives of orthopaedic and trauma surgery 2018-02, Vol.138 (2), p.165-171
• Main Authors: Balato, Giovanni, Franceschini, Vincenzo, Ascione, Tiziana, Lamberti, Alfredo, Balboni, Fiamma, Baldini, Andrea
• Format: Article
• Language: English
• Subjects: Accuracy; Joint surgery; Medical diagnosis; Medicine; Medicine & Public Health; Neutrophils; Orthopaedic Surgery; Orthopedics
• ISSN: 0936-8051; 1434-3916
• DOI: 10.1007/s00402-017-2832-6

Introduction This retrospective study was undertaken to define cut-off values for synovial fluid (SF) leukocyte count and neutrophil percentage for differentiating aseptic failure and periprosthetic joint infection (PJI) and to evaluate the diagnostic accuracy of blood inflammatory markers, and microbiological testing according to the criteria proposed by the International Consensus Meeting (ICM) of Philadelphia. Methods All patients who underwent revision total knee arthroplasty from January 2010 to July 2015 were included: we identified and classified 31 PJIs and 136 aseptic joints. The diagnostic performance of single test was assessed by receiver operating characteristic curve analyses. The sensitivity and specificity were calculated for each of the cut-off values and the area under the curve (AUC) was calculated. Results The median SF leukocyte count as well as the neutrophil percentage and inflammatory markers were significantly higher in patients with PJI than in those with aseptic failure ( p   2.8 × 10 3 /μL had a sensitivity of 83.8% and a specificity of 89.7% whereas a neutrophil percentage of > 72% yielded a marginally higher sensitivity of 84% and a specificity of 91%. Applying the ICM criteria we found a significant correlation between all these diagnostic measures and PJI ( p