Abstract
BACKGROUND: Relative humeral retrotorsion (rHRT) is an osseous adaptation in overhead athletes garnered from repetitive overhead throwing. Accurate measurement of anatomic humeral retrotorsion (aHRT) is important as it aids in the determination of rHRT, which influences glenohumeral range of motion profiles. While computed tomography scans are the gold standard for assessing aHRT, their limited clinical utility has driven interest in accessible alternatives, such as diagnostic ultrasound. PURPOSE/HYPOTHESIS: The purpose of this study was to validate a handheld ultrasound device (HH-US) as a clinically accessible tool to measure aHRT in baseball and softball athletes. It was hypothesized that a HH-US device will be reliable and valid when quantifying aHRT compared with an established benchmark, diagnostic musculoskeletal ultrasound (MSK-US). STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: Data were collected from collegiate baseball and softball athletes at 2 local universities. Participants were uninjured at the time of testing and over 17 years old. Anatomic HRT was measured bilaterally using both MSK-US (GE Venue Go) and handheld ultrasound (GE Vscan Air) using previously established methods. The intraclass correlation coefficient, standard error of measure, and minimal detectable change, as well as Bland-Altman plots, were used to assess reliability and agreement between devices, respectively. RESULTS: A total of 93 athletes were included in this study. HH-US had excellent intrarater reliability (ICC(2),(1) = 0.98; 95% CI, 0.94-0.97; SEM(90) = 1.77°; and MDC(90) = 4.12°). There was acceptable agreement between the HH-US and MSK-US. The mean difference between devices was -0.63° and 0.48° for the throwing and nonthrowing arms, respectively. Analysis of Bland-Altman plots demonstrated no significant bias across the range of measurements. HH-US measurements were completed in <2 minutes. CONCLUSION: Our study showed that HH-US provides a reliable and valid measurement of aHRT in comparison to MSK-US and may be an accessible option for clinicians evaluating overhead athletes. Given its strong agreement with established methods, HH-US offers an efficient and cost-effective alternative to MSK-US when measuring aHRT in baseball and softball athletes.