Ultrasonographic Assessment of Humeral Retrotorsion in Baseball Players

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. 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.