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Ultrasonographic assessment of humeral retrotorsion in baseball players: a validation study
Joseph B Myers1, Sakiko Oyama, John P Clarke
1University of North Carolina, Department of Exercise and Sport Science, Chapel Hill, NC 27599-8700, USA. joemyers@unc.edu
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.
Purpose:
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.
Study Design:
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.
Conclusion:
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.
