title: [18F]FDG PET accurately differentiates infected and non-infected non-unions after fracture fixation.
abstract: OBJECTIVE
  Complete fracture healing is crucial for good patient outcomes. A major complication in the treatment of fractures is non-union. The pathogenesis of non-unions is not always clear, although implant-associated infections play a significant role, especially after surgical treatment of open fractures. We aimed to evaluate the value of [18F]FDG PET in suspected infections of non-union fractures.
  
  
  METHODS
  We retrospectively evaluated 35 consecutive patients seen between 2000 and 2015 with suspected infection of non-union fractures, treated at a level I trauma center. The patients underwent either [18F]FDG PET/CT (N = 24), [18F]FDG PET (N = 11) plus additional CT (N = 8), or conventional X-ray (N = 3). Imaging findings were correlated with final diagnosis based on intraoperative culture or follow-up.
  
  
  RESULTS
  In 13 of 35 patients (37 %), infection was proven by either positive intraoperative tissue culture (N = 12) or positive follow-up (N = 1). [18F]FDG PET revealed 11 true-positive, 19 true-negative, three false-positive, and two false-negative results, indicating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 85 %, 86 %, 79 %, 90 %, and 86 %, respectively. The SUVmaxwas 6.4 ± 2.7 in the clinically infected group and 3.0 ± 1.7 in the clinically non-infected group (p <0.01). The SUVratiowas 5.3 ± 3.3 in the clinically infected group and 2.6 ± 1.5 in the clinically non-infected group (p <0.01).
  
  
  CONCLUSIONS
  [18F]FDG PET differentiates infected from non-infected non-unions with high accuracy in patients with suspected infections of non-union fractures, for whom other clinical findings were inconclusive for a local infection. [18F]FDG PET should be considered for therapeutic management of non-unions.
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Vera
authors.initials: V
authors.lastname: Wenter
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Nathalie L
authors.initials: NL
authors.lastname: Albert
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Brendel
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Wolfgang P
authors.initials: WP
authors.lastname: Fendler
authors.affiliation: Institute for Clinical Radiology, University of Munich, Munich, Germany.
authors.forename: Clemens C
authors.initials: CC
authors.lastname: Cyran
authors.affiliation: Department of Nuclear Medicine, University of Munich, Munich, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Bartenstein
authors.affiliation: Department of Reconstructive Arthroplasty, BG Trauma Center Murnau, Murnau, Germany.|Paracelsus Medical University, PMU Salzburg, Salzburg, Austria.
authors.forename: Jan
authors.initials: J
authors.lastname: Friederichs
authors.affiliation: Department of Reconstructive Arthroplasty, BG Trauma Center Murnau, Murnau, Germany.|Paracelsus Medical University, PMU Salzburg, Salzburg, Austria.
authors.forename: Jan-Philipp
authors.initials: JP
authors.lastname: Müller
authors.affiliation: Department of Reconstructive Arthroplasty, BG Trauma Center Murnau, Murnau, Germany.|Paracelsus Medical University, PMU Salzburg, Salzburg, Austria.
authors.forename: Matthias
authors.initials: M
authors.lastname: Militz
authors.affiliation: Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, University of Vienna, Währinger Gürtel 18-20, Floor 5L, 1090, Vienna, Austria. marcus.hacker@meduniwien.ac.at.
authors.forename: Marcus
authors.identifier: http://orcid.org/0000-0002-4222-4083
authors.initials: M
authors.lastname: Hacker
authors.affiliation: Department of Reconstructive Arthroplasty, BG Trauma Center Murnau, Murnau, Germany.|Paracelsus Medical University, PMU Salzburg, Salzburg, Austria.
authors.forename: Sven
authors.initials: S
authors.lastname: Hungerer
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D005260:Female; D019788:Fluorodeoxyglucose F18; D005592:Fracture Fixation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D019275:Radiopharmaceuticals; D014946:Wound Infection / Q000000981:diagnostic imaging*
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG; Fractures; Infection; Non-union; PET