Shoulder MRI Abnormalities in Asymptomatic Little League Baseball Players

Abstract

Background:Youth baseball is extremely popular in the United States, but it has been associated with shoulder pain and injury. The incidence of shoulder abnormalities in this athletic population has yet to be defined.Purpose:To examine abnormalities noted on magnetic resonance imaging (MRI) in the shoulders of asymptomatic Little League baseball players and to correlate these findings with the players’ throwing history and physical examinations.Study Design:Case-control study; Level of evidence, 3.Methods:A total of 23 Little League baseball players aged 10 to 12 years were recruited. All players underwent a comprehensive physical examination and responded to a questionnaire addressing their playing history and any arm or shoulder pain. Bilateral shoulder MRIs were performed and read in a blinded manner by 2 radiologists. Responses on the questionnaire and physical examination findings were compared between participants with and without positive MRI findings through use of chi-square test and analysis of variance.Results:The dominant arm was 8.5 times more likely to have an abnormality on MRI compared with the nondominant arm. In all, 12 players (52%) had 17 positive MRI findings in their throwing shoulder that were not present in their nondominant shoulder. These findings included edema or widening of the proximal humeral physis (n = 5), labral tear (n = 4), partial rotator thickness tear (n = 4), acromioclavicular joint abnormality (n = 2), subacromial bursitis (n = 1), and cystic change of the greater tuberosity (n = 1). Two primary risk factors were associated with an abnormal MRI: year-round play and single-sport athletes focusing solely on baseball (P < .05). Players with no risk factors, 1 risk factor, and both risk factors had a 25%, 71%, and 100% chance, respectively, of having an abnormal MRI. A majority of players (61%) had previously experienced shoulder pain, especially pitchers throwing curveballs and sliders (P < .05), but this was not associated with an abnormal MRI.Conclusion:Abnormalities seen on MRI involving the shoulder are common in Little League baseball players, especially those who are single-sport athletes playing year-round.

Progressive Elbow Magnetic Resonance Imaging Abnormalities in Little League Baseball Players Are Common: A 3-Year Longitudinal Evaluation

“…While most studies implicate overuse in the pathogenesis of these injuries, data are mixed regarding which specific metrics are most critical. This study is in agreement with mounting evidence 2,15,17 that year-round play is particularly harmful to the throwing arms of developing athletes. Erickson et al 2 showed that MLB pitchers from warm-weather climates, which may facilitate year-round play at a young age, were more likely to require UCL reconstruction and required surgery earlier in their careers compared with pitchers from cold-weather climates.…”

“…Similarly, early sport specialization has been shown to predispose young athletes across multiple sports to injury. 1,13,15 While the cause of throwing arm injuries in youth baseball players is undoubtedly multifactorial, continuous year-round play and early single-sport specialization seem to be significant contributors. We believe that serious consideration should be given to modifying the current guidelines for youth baseball players so that a minimum of 3 months of rest is no longer a nonenforced recommendation but a requirement that is enforced, similar to pitch count.…”

Prevalence and Consequences of Sport Specialization Among Little League Baseball Players

“…21 In a magnetic resonance imaging study of 23 asymptomatic Little League players, year-round participation in baseball and single-sport participation were associated with abnormal shoulder magnetic resonance imaging findings. 13,24 However, there have been no reports on the prevalence or consequences of sport specialization in large samples of Little League baseball players.…”

A Comparison of Team Sport Volume Surveyed Between High School and Club Sport Coaches

“…There is significant evidence that excessive sport volume is a risk factor for overuse injuries in youth and adolescent athletes. Participating in a single sport for more than 8 months out of the year has been identified as a risk factor in several studies of youth baseball pitchers 11 –13,19 as well as in broader samples of youth athletes from different sports. 1,17 Current recommendations suggest that youth athletes should not participate in more hours per week than the athlete’s age.…”