title: Comparison of dynamic ultrasound and stress radiology for assessment of inferior glenohumeral laxity in asymptomatic shoulders.
abstract: OBJECTIVE
  To determine the level of agreement between dynamic ultrasound imaging and stress radiography used for the measurement of inferior glenohumeral laxity in asymptomatic shoulders, and to determine the repeatability of the dynamic ultrasound technique.
  
  
  METHODS
  Using a custom-made stress device to apply an inferior displacement force of 90 N, we assessed 20 asymptomatic male subjects for inferior glenohumeral laxity, using stress radiography and dynamic ultrasound. Paired differences between the two methods were evaluated by the 95% limits of agreement method. At a separate session, 19 subjects had inferior glenohumeral laxity assessed by two observers, using dynamic ultrasound. Inter- and intra-observer repeatability was determined for the ultrasound technique.
  
  
  RESULTS
  The mean [(+/-standard deviation (SD)] inferior translation was 4.7+/-4.1 mm by stress radiography and 4.4+/-2.3 mm by dynamic ultrasound. The 95% limits of agreement showed good agreement between the two methods. The paired difference between the two measurement methods varied with the magnitude of the measurement (P<0.001). Intra-observer repeatability of dynamic ultrasound was determined by the use of intra-class correlation coefficients and was 0.94 and 0.89 for the two investigators. Inter-observer repeatability was 0.85. The standard error of the measurement was 0.60 mm and 0.66 mm, for repeated measurements by the two investigators, and 0.85 mm between investigators. Repeatability coefficients demonstrated excellent consistency of measurement between sessions and good consistency between observers.
  
  
  CONCLUSIONS
  Dynamic ultrasound is a valid and reproducible method for the assessment and quantification of inferior glenohumeral laxity.
authors.affiliation: Department of Orthopaedic & Accident Surgery, Queen's Medical Centre Campus, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: S C
authors.initials: SC
authors.lastname: Cheng
authors.forename: D
authors.initials: D
authors.lastname: Hulse
authors.forename: K J
authors.initials: KJ
authors.lastname: Fairbairn
authors.forename: M
authors.initials: M
authors.lastname: Clarke
authors.forename: W A
authors.initials: WA
authors.lastname: Wallace
mesh_terms: D000293:Adolescent; D000328:Adult; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis*; D008297:Male; D015588:Observer Variation; D011859:Radiography; D015203:Reproducibility of Results; D012785:Shoulder Joint / Q000000981:diagnostic imaging*; D014463:Ultrasonography; D016474:Weight-Bearing