title: The Impact of Three-Dimensional CT Imaging on Intraobserver and Interobserver Reliability of Proximal Humeral Fracture Classifications and Treatment Recommendations.
abstract: BACKGROUND
  The classification systems for fractures of the proximal part of the humerus provide low interobserver and intraobserver reliability when radiographs or two-dimensional computed tomography scans are used. The purpose of this investigation was to determine whether the use of three-dimensional computed tomography scans could improve interobserver and intraobserver reliability of AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) and Neer classifications and treatment recommendations.
  
  
  METHODS
  Two trauma surgeons, one shoulder surgeon, two senior orthopaedic residents, and two junior orthopaedic residents reviewed the radiographs and two and three-dimensional computed tomography scans of forty fractures of the proximal part of the humerus. Each imaging modality was reviewed in isolation, and fractures were classified according to the Neer and AO/OTA classifications and treatment recommendations were provided. This process was repeated for intraobserver analysis. Interobserver agreement was calculated within and between levels of training for each classification and treatment recommendation with respect to radiographs and two and three-dimensional computed tomography scans.
  
  
  RESULTS
  Among attending orthopaedic surgeons and senior residents, the use of three-dimensional computed tomography did not improve agreement compared with the use of two-dimensional computed tomography for the Neer classification based on planes, the AO/OTA classification, or the treatment recommendation, but it did improve agreement among junior residents. Comparing between levels of training, three-dimensional computed tomography increased agreement only between junior residents and more experienced reviewers for the Neer classification based on planes and for the AO/OTA classification but not for the treatment recommendation. Intraobserver agreement for each reviewer for classification and treatment ranged from slight to fair and was not improved through the use of three-dimensional computed tomography.
  
  
  CONCLUSIONS
  In this investigation, the use of three-dimensional computed tomography imaging did not offer improved interobserver and intraobserver agreement compared with the use of two-dimensional computed tomography imaging with regard to classification and treatment of fractures of the proximal part of the humerus, except among reviewers with limited clinical experience.
  
  
  METHODS
  Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Marschall B
authors.initials: MB
authors.lastname: Berkes
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dines
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Milton T M
authors.initials: MT
authors.lastname: Little
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Garner
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Grant Daniel
authors.initials: GD
authors.lastname: Shifflett
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Lionel E
authors.initials: LE
authors.lastname: Lazaro
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: David S
authors.initials: DS
authors.lastname: Wellman
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: David M
authors.initials: DM
authors.lastname: Dines
authors.affiliation: Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021. E-mail address for M.B. Berkes: marschall.berkes@gmail.com.
authors.forename: Dean G
authors.initials: DG
authors.lastname: Lorich
mesh_terms: D006801:Humans; D021621:Imaging, Three-Dimensional; D015588:Observer Variation; D017410:Practice Guidelines as Topic; D011859:Radiography; D015203:Reproducibility of Results; D012784:Shoulder Fractures / Q000145:classification* / Q000000981:diagnostic imaging* / Q000628:therapy; D014057:Tomography, X-Ray Computed / Q000379:methods