title: Reliability of freehand three-dimensional ultrasound to measure scapular rotations.
abstract: The objective of this study was to evaluate the reliability of using freehand three-dimensional ultrasound to measure scapular rotations (internal/external, upward/downward, anterior/posterior). The scapular position in 22 healthy, nondisabled individuals was imaged three times in four testing positions of interest (arm at rest and humeral elevation in the sagittal, frontal, and scapular planes). We found substantial reliability across scanning positions and scapular rotations, with intraclass correlation coefficients ranging from 0.62 to 0.95. The highest reliability was found in the rest testing position. Our standard error of measurement was less than 2 degrees for all measurements and less than 0.5 degrees for most. Minimum detectable change ranged from 0.37 to 3.08 degrees. Our results agree with the pattern of movement found in other studies, with the scapula moving toward a more externally rotated, upwardly rotated, and posteriorly tilted position with humeral elevation. Further study is warranted to compare our methods to a gold standard, apply them to evaluating dynamic movement, and determine whether they can be used to detect shoulder pathology.
authors.affiliation: Human Engineering Research Laboratories, Department of Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA; Departments of.
authors.forename: Lynn A
authors.initials: LA
authors.lastname: Worobey
authors.forename: Ima A
authors.initials: IA
authors.lastname: Udofa
authors.forename: Yen-Sheng
authors.initials: YS
authors.lastname: Lin
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Koontz
authors.forename: Shawn S
authors.initials: SS
authors.lastname: Farrokhi
authors.forename: Michael L
authors.initials: ML
authors.lastname: Boninger
mesh_terms: D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement; D016059:Range of Motion, Articular; D015203:Reproducibility of Results; D012399:Rotation; D012540:Scapula / Q000000981:diagnostic imaging / Q000503:physiopathology*; D019534:Shoulder Impingement Syndrome / Q000000981:diagnostic imaging* / Q000503:physiopathology; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D014463:Ultrasonography
keywords: anterior/posterior tilting; freehand ultrasound; humeral elevation; internal/external rotation; minimum detectable change; reliability; rotation; scapula; standard error of measurement; upward/downward rotation