Alpha-defensin as a diagnostic tool in revision total knee arthroplasties with unexpected positive intraoperative cultures and unexpected culture negative intraoperative cultures

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA sports traumatology, arthroscopy : official journal of the ESSKA, 2023-04, Vol.31 (4), p.1462-1469
• Main Authors: Simon, Sebastian, Frank, Bernhard J. H., Aichmair, Alexander, Dominkus, Martin, Mitterer, Jennyfer A., Hartmann, Susana Gardete, Kasparek, Michael, Hofstaetter, Jochen G.
• Format: Article
• Language: English
• Subjects: alpha-Defensins; Antibiotic resistance; Arthroplasty, Replacement, Hip; Arthroplasty, Replacement, Knee - adverse effects; Biomarkers - analysis; Centrifugation; Cross Infection; Enzyme-linked immunosorbent assay; Epidermis; Humans; Infections; Joint diseases; Knee; Medical diagnosis; Medicine; Medicine & Public Health; Methicillin; Methicillin-Resistant Staphylococcus aureus; Microorganisms; Orthopedics; Pathogens; Prosthesis-Related Infections - diagnosis; Prosthesis-Related Infections - microbiology; Retrospective Studies; Revisions; Sensitivity and Specificity; Sports Medicine; Synovial fluid; Synovial Fluid - chemistry; Virulence
• ISSN: 0942-2056; 1433-7347
• DOI: 10.1007/s00167-022-07268-w

Purpose Unexpected-positive-intraoperative-cultures (UPIC) are common in presumed aseptic revision-total-knee-arthroplasties (rTKA). However, the clinical significance is not entirely clear. In contrast, in some presumably septic rTKA, identification of an underlying pathogen was not possible, so-called unexpected-negative-intraoperative-cultures (UNIC). The purpose of this study was to evaluate the potential use of synovial alpha-defensin (AD) levels in these patients. Methods Synovial AD levels from 143 rTKAs were evaluated retrospectively from our prospectively maintained institutional periprostetic joint infection (PJI) biobank and database. The 2018-International Consensus Meeting (ICM) criteria was used to define the study groups. Samples from UPICs with a minimum of one positive intraoperative culture (ICM 2- ≥ 6) ( n  = 20) and UNIC’s (ICM ≥ 6) ( n  = 14) were compared to 34 septic culture-positive samples (ICM ≥ 6) and 75 aseptic culture-negative (ICM 0-1). Moreover, AD-lateral-flow-assay (ADLF) and an enzyme-linked-immunosorbent-assay (ELISA) in detecting the presence of AD in native and centrifuged synovial fluid specimens was performed. Concentration of AD determined by ELISA and ADLF methods, as well as microbiological, and histopathological results, serum and synovial parameters along with demographic factors were analysed. Results AD was positive in 31/34 (91.2%) samples from the septic culture-positive group and in 14/14 (100%) samples in the UNIC group. All UPIC samples showed a negative AD result. Positive AD samples were highly associated with culture positive and histopathological results ( p