Pytiak Andrew V, Stearns Phillip, Bastrom Tracey P, Dwek Jerry, Kruk Peter, Roocroft Joanna H, Pennock Andrew T
Orthopedics & Scoliosis Division, Rady Children's Hospital, San Diego, California, USA.
Department of Orthopedic Surgery, University of California, San Diego, California, USA.
Orthop J Sports Med. 2017 May 19;5(5):2325967117704851. doi: 10.1177/2325967117704851. eCollection 2017 May.
Little League throwing guidelines have recently been implemented in an attempt to lessen the growing number of elbow injuries occurring in youth baseball players.
HYPOTHESIS/PURPOSE: The purpose of this study was to examine pre- and postseason changes seen on magnetic resonance imaging (MRI) in youth baseball players' elbows in an attempt to identify risk factors for pain and MRI abnormalities, with a particular focus on the current Little League guidelines. We hypothesized that MRI abnormalities would be common in pitchers with high pitch counts and poor guideline compliance.
Cohort study; Level of evidence, 2.
A prospective study of Little League players aged 10 to 13 years was performed. Players were recruited prior to the start of the season and underwent bilateral elbow MRI as well as a physical examination and completed a questionnaire addressing their playing history and arm pain. At the end of the season, a repeat MRI and physical examination were performed. MRIs were read by blinded radiologists. During the season, player statistics including innings played, pitch counts, and guideline compliance were recorded. Physical examination findings and player statistics were compared between subjects with and without MRI changes utilizing chi-square and analysis of variance techniques.
Twenty-six players were enrolled. Despite 100% compliance with pitching guidelines, 12 players (48%) had abnormal MRI findings, and 28% experienced pain during the season. There was a significant difference in distal humeral physeal width measured pre- to postseason (1.54 vs 2.31 mm, < .001). There was a significant loss of shoulder internal rotation during the season, averaging 11°. While pitch counts, player position, and throwing curveballs/sliders were not significantly associated with changes seen on MRI, year-round play was associated with abnormalities ( < .05). Much lower compliance (<50%) was observed with nonenforced guidelines, including avoidance of single-sport specialization, year-round play, and throwing curveballs/sliders.
Arm pain and MRI abnormalities of the medial elbow are common in Little League baseball players who comply with the Little League throwing guidelines, especially those playing year-round.
最近实施了青少年棒球投球指南，试图减少青少年棒球运动员肘部损伤不断增加的数量。
假设/目的：本研究的目的是检查青少年棒球运动员肘部在赛季前和赛季后的磁共振成像（MRI）变化，以试图确定疼痛和MRI异常的风险因素，特别关注当前的青少年棒球指南。我们假设MRI异常在投球次数多且指南依从性差的投手中很常见。
队列研究；证据等级，2级。
对10至13岁的青少年棒球运动员进行了一项前瞻性研究。在赛季开始前招募球员，对其双侧肘部进行MRI检查以及体格检查，并完成一份关于他们比赛历史和手臂疼痛的问卷。在赛季结束时，进行重复的MRI检查和体格检查。MRI由不知情的放射科医生解读。在赛季期间，记录球员的统计数据，包括投球局数、投球次数和指南依从性。使用卡方检验和方差分析技术比较有和没有MRI变化的受试者之间的体格检查结果和球员统计数据。
招募了26名球员。尽管100%遵守投球指南，但12名球员（48%）有MRI异常发现，28%在赛季中经历了疼痛。赛季前和赛季后测量的肱骨远端骨骺宽度有显著差异（1.54对2.31毫米，P<0.001）。赛季期间肩部内旋有显著丧失，平均为11°。虽然投球次数、球员位置以及投曲线球/滑球与MRI上看到的变化没有显著相关性，但全年参赛与异常有关（P<0.05）。对于未强制执行的指南，包括避免单一运动专项化、全年参赛以及投曲线球/滑球，观察到的依从性要低得多（<50%）。
在遵守青少年棒球投球指南的青少年棒球运动员中，尤其是那些全年参赛的运动员，手臂疼痛和内侧肘部MRI异常很常见。
