title: Measurement of thoracic and lumbar fracture kyphosis: evaluation of intraobserver, interobserver, and technique variability.
abstract: METHODS
  Statistical analysis of various measurement techniques for thoracolumbar burst fracture kyphosis on lateral radiograph.
  
  
  OBJECTIVE
  To determine the most reliable measurement technique.
  
  
  BACKGROUND
  The treatment of thoracic and lumbar burst fractures involves many factors, including the degree of resultant kyphosis. Although various methods have been described, no study has directly compared these methods for reliability and reproducibility.
  
  
  METHODS
  Fifty lateral radiographs of thoracic and lumbar burst fractures were randomly selected and measured on two separate occasions by three spine surgeons using five different measurement techniques. Radiograph quality, fracture type, and the center beam location were determined. Statistical analysis included analysis of variance for repeated measures and analysis of variance using a generalized linear model.
  
  
  RESULTS
  Intraclass correlation coefficients were most consistent for Method 1 (rho = 0.83-0.94) followed by Method 4 (rho = 0.65-0.89) and Method 5 (rho = 0.73-0. 85). Intraobserver agreement (% of repeated measures within 5 degrees of the original measurement) ranged between 72% and 98% for all techniques for all three observers, with Method 1 showing the best agreement (84%-98%). Paired comparisons between observers varied considerably with interobserver reliability correlation coefficients ranging from 0.52 to 0.93. Method 1 showed the highest interobserver reliability coefficient (0.81, range 0.71-0.93) followed by Method 5 (0.71, range 0.68-0.75). Method 1 also had the highest percentage of agreement within categories (90% within 5 degrees ).
  
  
  CONCLUSIONS
  Method 1 (measuring from the superior endplate of the vertebral body one level above the injured vertebral body to the inferior endplate of the vertebral body one level below) showed the best intraobserver and interobserver reliability overall.
authors.affiliation: Orthopaedic Surgery Service, Walter Reed Army Medical Center, Washington, DC 20307, USA.
authors.forename: T R
authors.initials: TR
authors.lastname: Kuklo
authors.forename: D W
authors.initials: DW
authors.lastname: Polly
authors.forename: B D
authors.initials: BD
authors.lastname: Owens
authors.forename: S M
authors.initials: SM
authors.lastname: Zeidman
authors.forename: A S
authors.initials: AS
authors.lastname: Chang
authors.forename: W R
authors.initials: WR
authors.lastname: Klemme
mesh_terms: D000704:Analysis of Variance; D016001:Confidence Intervals; D006801:Humans; D007738:Kyphosis / Q000000981:diagnostic imaging*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging* / Q000293:injuries; D015588:Observer Variation; D011336:Probability; D011859:Radiography; D015203:Reproducibility of Results; D016103:Spinal Fractures / Q000000981:diagnostic imaging*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging* / Q000293:injuries