title: Sensitivity of frozen section histology for identifying Propionibacterium acnes infections in revision shoulder arthroplasty.
abstract: BACKGROUND
  Propionibacterium acnes is a clinically relevant pathogen with total shoulder arthroplasty. The purpose of this study was to determine the sensitivity of frozen section histology in identifying patients with Propionibacterium acnes infection during revision total shoulder arthroplasty and investigate various diagnostic thresholds of acute inflammation that may improve frozen section performance.
  
  
  METHODS
  We reviewed the results of forty-five patients who underwent revision total shoulder arthroplasty. Patients were divided into the non-infection group (n = 15), the Propionibacterium acnes infection group (n = 18), and the other infection group (n = 12). Routine preoperative testing was performed and intraoperative tissue culture and frozen section histology were collected for each patient. The histologic diagnosis was determined by one pathologist for each of the four different thresholds. The absolute maximum polymorphonuclear leukocyte concentration was used to construct a receiver operating characteristics curve to determine a new potential optimal threshold.
  
  
  RESULTS
  Using the current thresholds for grading frozen section histology, the sensitivity was lower for the Propionibacterium acnes infection group (50%) compared with the other infection group (67%). The specificity of frozen section was 100%. Using a receiver operating characteristics curve, an optimized threshold was found at a total of ten polymorphonuclear leukocytes in five high-power fields (400×). Using this threshold, the sensitivity of frozen section for Propionibacterium acnes was increased to 72%, and the specificity remained at 100%.
  
  
  CONCLUSIONS
  Using current histopathology grading systems, frozen sections were specific but showed low sensitivity with respect to the Propionibacterium acnes infection. A new threshold value of a total of ten or more polymorphonuclear leukocytes in five high-power fields may increase the sensitivity of frozen section, with minimal impact on specificity.
authors.affiliation: Department of Orthopedic Surgery, Building A-41 (M.J.G., S.J.F., E.T.R., and J.P.I.), and Department of Anatomic Pathology, Building L-25 (T.W.B.), Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195. E-mail address for M.J. Grosso: mgrosso13@gmail.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Grosso
authors.affiliation: Department of Orthopedic Surgery, Building A-41 (M.J.G., S.J.F., E.T.R., and J.P.I.), and Department of Anatomic Pathology, Building L-25 (T.W.B.), Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195. E-mail address for M.J. Grosso: mgrosso13@gmail.
authors.forename: Salvatore J
authors.initials: SJ
authors.lastname: Frangiamore
authors.affiliation: Department of Orthopedic Surgery, Building A-41 (M.J.G., S.J.F., E.T.R., and J.P.I.), and Department of Anatomic Pathology, Building L-25 (T.W.B.), Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195. E-mail address for M.J. Grosso: mgrosso13@gmail.
authors.forename: Eric T
authors.initials: ET
authors.lastname: Ricchetti
authors.affiliation: Department of Orthopedic Surgery, Building A-41 (M.J.G., S.J.F., E.T.R., and J.P.I.), and Department of Anatomic Pathology, Building L-25 (T.W.B.), Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195. E-mail address for M.J. Grosso: mgrosso13@gmail.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Bauer
authors.affiliation: Department of Orthopedic Surgery, Building A-41 (M.J.G., S.J.F., E.T.R., and J.P.I.), and Department of Anatomic Pathology, Building L-25 (T.W.B.), Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195. E-mail address for M.J. Grosso: mgrosso13@gmail.
authors.forename: Joseph P
authors.initials: JP
authors.lastname: Iannotti
mesh_terms: D000368:Aged; D001178:Arthroplasty / Q000009:adverse effects*; D005260:Female; D005629:Frozen Sections; D016908:Gram-Positive Bacterial Infections / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011425:Propionibacterium acnes / Q000302:isolation & purification*; D016459:Prosthesis-Related Infections / Q000175:diagnosis* / Q000382:microbiology; D012086:Reoperation; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000382:microbiology / Q000601:surgery*