title: Interobserver agreement for Letournel acetabular fracture classification with multidetector CT: are standard Judet radiographs necessary?
abstract: OBJECTIVE
  To retrospectively evaluate interobserver agreement for Letournel acetabular fracture classification with radiography alone and multidetector computed tomography (CT) alone and to retrospectively assess whether standard Judet views lead to a change in the classification.
  
  
  METHODS
  Institutional review board approval was obtained; informed consent was not required for this HIPAA-compliant study, which included 101 imaging studies performed in 99 patients (78 male, 21 female; mean age, 43 years; age range, 15-86 years) with acetabular fractures. Two musculoskeletal radiologists independently classified the fractures with radiography alone and multidetector CT alone. Multiplanar reformatted and three-dimensional (3D) CT images were reviewed at a computer workstation. Readers were shown radiographs at the end of multidetector CT image reading to see if this would change the multidetector CT-based classification. kappa Values were calculated to assess interobserver agreement. For surgically treated patients, the McNemar test was used to compare the accuracy of readers' classifications. The reference standard was a combination of preoperative radiographic and multidetector CT image findings and intraoperative findings.
  
  
  RESULTS
  Interobserver agreement was moderate (kappa = 0.42) with radiography and substantial (kappa = 0.70) with multidetector CT. Multidetector CT classification was changed in two cases (one case for each reader) after standard Judet views were added. In 73 surgically treated patients, agreement with the surgeons' classification was higher with multidetector CT than with radiography (P < .01 for one reader, P = .06 for the other reader).
  
  
  CONCLUSIONS
  There is substantial interobserver agreement for Letournel acetabular fracture classification with multiplanar reformatted and 3D multidetector CT images. Standard Judet pelvic radiographs add little information for changing the multidetector CT classification.
authors.affiliation: Department of Radiology, University of Iowa Roy J. and Lucille A. Carver College of Medicine, 200 Hawkins Dr, Iowa City, IA 52242, USA. kenjirou-ohashi@uiowa.edu
authors.forename: Kenjirou
authors.initials: K
authors.lastname: Ohashi
authors.forename: Georges Y
authors.initials: GY
authors.lastname: El-Khoury
authors.forename: Khalil W
authors.initials: KW
authors.lastname: Abu-Zahra
authors.forename: Kevin S
authors.initials: KS
authors.lastname: Berbaum
mesh_terms: D000077:Acetabulum / Q000293:injuries*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006620:Hip Fractures / Q000145:classification* / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*