title: Ultrasonographic assessment of humeral retrotorsion in baseball players: a validation study.
abstract: BACKGROUND
  Recently, clinicians and researchers started using diagnostic ultrasound to measure humeral torsion as an alternative to radiological assessments in overhead-throwing athletes and other clinical populations. Ultrasound appears to be a reliable, nonradiological alternative, but ultrasound assessment has not been validated against computed tomography (CT), the current gold standard.
  
  
  OBJECTIVE
  This study aimed to establish the validity of an ultrasound assessment of humeral torsion by comparing data obtained using both ultrasound and CT, the current standard.
  
  
  METHODS
  Cohort study (Diagnosis); Level of evidence, 2.
  
  
  METHODS
  Humeral torsion was measured using both ultrasound and CT in 24 collegiate-aged baseball players. Comparisons between the assessments were made using both regression and Bland-Altman plots. Reliability and precision were also established.
  
  
  RESULTS
  A strong relationship existed between humeral torsion variables obtained with ultrasound and CT (R = .797, R (2) = .635, P < .001). The ultrasound assessment yielded reliability coefficients ranging from .991 to .997, with approximately 1° of measurement error. The CT method's reliability coefficients ranged from .805 to .933, with approximately 3.5° of measurement error.
  
  
  CONCLUSIONS
  There was a strong relationship between humeral torsion obtained with ultrasound and CT, the current standard of assessment. Ultrasound provides a reliable, valid alternative to CT for obtaining an indication of the amount of humeral torsion in the upper extremity.
authors.affiliation: University of North Carolina, Department of Exercise and Sport Science, Chapel Hill, NC 27599-8700, USA. joemyers@unc.edu
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Myers
authors.forename: Sakiko
authors.initials: S
authors.lastname: Oyama
authors.forename: John P
authors.initials: JP
authors.lastname: Clarke
mesh_terms: D000328:Adult; D001484:Baseball; D060751:Bone Retroversion / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D006801:Humans; D006811:Humerus / Q000000981:diagnostic imaging* / Q000473:pathology; D016014:Linear Models; D008297:Male; D015588:Observer Variation; D015203:Reproducibility of Results; D012785:Shoulder Joint / Q000000981:diagnostic imaging* / Q000473:pathology; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography