Investigation of Ultrasound as a Diagnostic Imaging Modality for Little League Shoulder

Abstract

Objective Ultrasound (US) is an established imaging modality in adult sports medicine but is not commonly used in the diagnosis of pediatric sports conditions, such as Little League shoulder (LLS). This study was conducted to determine the reliability of US measurement of width of the physis at the proximal humerus in diagnosed LLS and to compare US to radiography (RA) in detecting a difference between the affected (dominant) (A) and unaffected (U) shoulders. Materials and Methods Ten male baseball players diagnosed with LLS were enrolled in the study. US images of the proximal humeral physis at the greater tuberosity of both shoulders were obtained by an US-trained sports medicine physician, and the physeal width was measured. Blinded to prior measurements, a separate physician performed measurements on the stored US images. Measurements were compared with RA on the anteroposterior (AP) view for both A and U at the time of the initial visit and for A at follow-up. Results The physeal width (mm) at A and U at the initial visit averaged 5.94 ± 1.69 and 4.36 ± 1.20 respectively on RA, and 4.15 ± 1.12 and 3.40 ± 0.85 on US. Median difference of averaged US measurements between A and U at initial evaluation was 0.75 mm (p = 0.00016). A linear model showed US measurements to be predictive of RA on A (R2 = 0.51) and U (R2 = 0.48). Conclusion US was able to reliably measure the width of the proximal humeral physis and detect a difference between A and U. US correlated well with RA (standard for LLS). US should be considered by the US-trained physician for the diagnosis of LLS.