title: Measurement of ulnar variance from the lateral radiograph: a comparison of techniques.
abstract: OBJECTIVE
  To determine the reliability of measuring ulnar variance on lateral wrist radiographs and to compare this technique with previously described methods.
  
  
  METHODS
  Ulnar variance was measured in 100 normal wrist radiographs using the methods of perpendiculars, central reference point, and the lateral radiograph by 3 surgeons on 2 occasions. Intraobserver repeatability and agreement between raters and methods were assessed and compared.
  
  
  RESULTS
  Intra- and interobserver reliability and agreement were both excellent using all 3 methods within a ± 1.0-mm cutoff. However, there was substantial pairwise disagreement in measures of ulnar variance between all 3 methods.
  
  
  CONCLUSIONS
  This study demonstrates that, for measurement of ulnar variance, the methods of perpendiculars, central reference point, and lateral radiographic measurement each have clinically acceptable intraobserver repeatability and interobserver agreement. Despite their independent reliability, each method of radiographic determination of ulnar variance had considerable disagreement with the other methods, indicative of inherent inaccuracies in the techniques. The lateral radiograph uniquely allows for visualization of the amount of ulnar head protruding proximal or distal to the concave lunate facet and allows for a rapid estimation of pronosupination, which is known to affect ulnar variance.
  
  
  CONCLUSIONS
  Determination of ulnar variance can be an important component of surgical decision making in various pathological conditions of the hand and wrist. Traditionally, it has been measured through methods using the posteroanterior wrist radiograph, but there are potential shortcomings with these methods, and use of the lateral radiograph may provide a more clinically relevant picture of ulnar variance. This study shows that measurement from the lateral radiograph provides similar reliability to previously accepted techniques.
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Parker
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX.
authors.forename: Minh
authors.initials: M
authors.lastname: Nguyen
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX.
authors.forename: Charles G
authors.initials: CG
authors.lastname: Minard
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX.
authors.forename: Danielle
authors.initials: D
authors.lastname: Guffey
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX.
authors.forename: Marc H
authors.initials: MH
authors.lastname: Willis
authors.affiliation: Department of Orthopedic Surgery, Baylor College of Medicine, Ben Taub General Hospital, Houston, TX; Dan L. Duncan Institute for Clinical and Translational Research, Baylor College of Medicine, Houston, TX; Department of Radiology, Baylor College of Medicine, Houston, TX. Electronic address: leereichel@gmail.com.
authors.forename: Lee M
authors.initials: LM
authors.lastname: Reichel
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D011884:Radius / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D015203:Reproducibility of Results; D014457:Ulna / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D014955:Wrist Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*
keywords: Ulnar variance; comparison; lateral; measurement; radiograph