title: Simple overlay device for determining radial head and neck height.
abstract: BACKGROUND
  The purpose of this study was to test the hypothesis that a simple overlay device can be used on radiographs to measure radial head and neck height.
  
  
  METHODS
  Thirty anteroposterior elbow radiographs from 30 patients with a clinical diagnosis of lateral epicondylitis were examined to measure radial head and neck height. Three methods using different points along the bicipital tuberosity as a landmark were used. Method 1 used the proximal end of the bicipital tuberosity, method 2 used the most prominent point of the bicipital tuberosity, and method 3 used a simple overlay device (SOD) template that was aligned with anatomic reference points. All measurements were performed three times by three observers to determine interobserver and intraobserver reliability.
  
  
  RESULTS
  Intraclass correlation coefficients revealed higher interobserver and intraobserver correlations for the SOD template method than for the other two methods. The 95% limits of agreement between observers were markedly better (-1.8 mm to +1.0 mm) for the SOD template method than for the proximal point method (-3.8 mm to +3.4 mm) or the prominent point method (-5.9 mm to +4.9 mm).
  
  
  CONCLUSIONS
  We found that the SOD template method was reliable for assessing radial head and neck height. It had less variability than other methods, its 95% limit of agreement being less than 2 mm. This method could be helpful for assessing whether or not the insertion of a radial head prosthesis has resulted in over-lengthening of the radius.
authors.affiliation: Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN 55905, USA. moonjg@korea.ac.kr
authors.forename: Jun-Gyu
authors.initials: JG
authors.lastname: Moon
authors.forename: Richard D
authors.initials: RD
authors.lastname: Southgate
authors.forename: James S
authors.initials: JS
authors.lastname: Fitzsimmons
authors.forename: Shawn W
authors.initials: SW
authors.lastname: O'Driscoll
mesh_terms: D000328:Adult; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography / Q000295:instrumentation*; D011884:Radius / Q000000981:diagnostic imaging* / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013716:Tennis Elbow / Q000000981:diagnostic imaging* / Q000473:pathology*; D014962:X-Ray Film