Maturation-dependent findings in the shoulders of pediatric baseball players on magnetic resonance imaging.

PURPOSE

To compare the prevalence and characteristics of shoulder osseous and soft tissue findings on magnetic resonance imaging (MRI) with respect to skeletal maturation in symptomatic pediatric baseball players without a history of acute trauma.

METHODS

The IRB-approved, HIPAA-compliant retrospective study analyzed 87 consecutive pediatric baseball players (86 boys and 1 girl; mean age, 15.4 ± 2.1 years) with shoulder MRI performed between March 1, 2012 and September 30, 2017. In consensus, two radiologists assessed the MRI studies for findings involving the humerus, the glenoid, the labrum, the rotator cuff, and the acromioclavicular joint. Exact Cochran-Armitage trend and Mantel-Haenszel Chi-square tests were used to investigate the association between these findings and skeletal maturation.

RESULTS

The mean ages between players who are skeletally immature (37 shoulders), maturing (26 shoulders), and matured (24 shoulders) were significantly different (p < 0.001). Bone marrow edema (p < 0.001) and sclerosis (p < 0.001) within the proximal humeral metaphysis decreased with skeletal maturation. Glenoid remodeling (p = 0.038) was more severe in the skeletally immature players and the prevalence of Bennett lesions (p = 0.048) increased with skeletal maturation. The prevalence of labral tears, rotator cuff tendinosis, and acromioclavicular joint separation did not significantly change with skeletal maturation.

CONCLUSIONS

The change in the prevalence of findings within the proximal humerus and glenoid with skeletal maturation suggest differences in the distribution of stress within the shoulders of pediatric baseball players during development.