Uchida Tomoya, Matsuo Tomoyuki, Sakata Jun, Yamaguchi Haruno, Nishizawa Izumi, Sakai Tadahiro
Department of Health and Sport Sciences, Graduate School of Medicine, Osaka University, Toyonaka, Japan; Toyota Athlete Support Center, Toyota Memorial Hospital, Toyota, Japan.
Department of Health and Sport Sciences, Graduate School of Medicine, Osaka University, Toyonaka, Japan.
J Shoulder Elbow Surg. 2025 Apr;34(4):962-970. doi: 10.1016/j.jse.2024.07.026. Epub 2024 Sep 7.
The posterosuperior humeral head contacts the glenoid during pitching. While magnetic resonance imaging often detects abnormalities in the posterosuperior humeral head of baseball pitchers, ultrasonography may also be effective in identifying these abnormalities. However, studies on such abnormalities in asymptomatic players are limited. Thus, this study aimed to determine the prevalence of abnormal findings in the humeral head using ultrasonography in asymptomatic collegiate baseball pitchers.
We utilized ultrasonography to assess abnormal findings in the humeral head, defined as a break in continuity or an irregular surface around the infraspinatus insertion, in 33 college baseball pitchers (pitcher group) and 30 college students without experience in overhead sports (control group). For 11 of the 33 pitchers, computed tomography-like images were used to locate the abnormalities. The location was quantitatively identified in the axial plane using a clock system, with the bicipital groove designated as 12 o'clock, and qualitatively assessed in the sagittal plane. Shoulder internal and external rotation ranges of motion (IR and ER ROMs) and humeral retroversion were measured using an inclinometer. The prevalence of abnormalities among the 4 subgroups (throwing and nonthrowing shoulders of the pitcher group and dominant and nondominant shoulders of the control group) was compared using the Fisher's exact test. A paired t-test was also performed to compare the IR and ER ROMs, as well as the humeral retroversion between each group's throwing (dominant) and nonthrowing (nondominant) sides.
The prevalence of abnormalities was significantly higher (76%) in the throwing shoulder of the pitcher group than in the other shoulder groups (<.001). The mean position of the humeral head abnormalities in the axial plane was 8:32 ± 0:21 in the clock system, with all abnormalities located at the infraspinatus insertion on the greater tuberosity in the sagittal plane according to CT-like image analysis. While ER ROM and humeral retroversion were greater in the throwing shoulder, IR ROM was less than that in the non-throwing shoulder in the pitcher group (<.001).
Ultrasonographic assessments revealed a higher prevalence of abnormalities in humeral head for asymptomatic collegiate baseball pitchers. Repetitive throwing motions may lead not only to adaptations in the ROM of the shoulder joint but also to abnormalities in the humeral head. Thus, ultrasonography may help identify asymptomatic baseball players with physiological internal impingement.
在投球过程中，肱骨头后上部与关节盂相接触。虽然磁共振成像常常能检测出棒球投手肱骨头后上部的异常，但超声检查在识别这些异常方面可能也很有效。然而，关于无症状运动员此类异常的研究有限。因此，本研究旨在通过超声检查确定无症状大学棒球投手肱骨头异常发现的患病率。
我们利用超声检查评估了33名大学棒球投手（投手组）和30名无过头运动经验的大学生（对照组）肱骨头的异常发现，异常发现定义为冈下肌附着处连续性中断或表面不规则。对于33名投手中的11名，使用类似计算机断层扫描的图像来定位异常。在轴向平面上使用时钟系统对位置进行定量识别，将二头肌沟指定为12点，并在矢状平面上进行定性评估。使用倾角仪测量肩部内旋和外旋活动范围（IR和ER ROM）以及肱骨后倾。使用Fisher精确检验比较4个亚组（投手组的投球肩和非投球肩以及对照组的优势肩和非优势肩）中异常的患病率。还进行了配对t检验，以比较每组投球（优势）侧和非投球（非优势）侧的IR和ER ROM以及肱骨后倾。
投手组投球肩的异常患病率（76%）显著高于其他肩组（<.001）。根据类似CT图像分析，在时钟系统中，肱骨头异常在轴向平面的平均位置为8:32 ± 0:21，在矢状平面上所有异常均位于大结节上的冈下肌附着处。虽然投手组投球肩的ER ROM和肱骨后倾更大，但IR ROM小于非投球肩（<.001）。
超声检查评估显示，无症状大学棒球投手肱骨头异常的患病率较高。重复性投球动作不仅可能导致肩关节活动范围的适应性变化，还可能导致肱骨头异常。因此，超声检查可能有助于识别患有生理性内部撞击的无症状棒球运动员。
