Yokoya Shin, Harada Yohei, Negi Hiroshi, Matsushita Ryosuke, Matsubara Norimasa, Sumimoto Yasuhiko, Adachi Nobuo
Department of Orthopaedic Surgery, Graduate School of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
JSES Int. 2021 May 10;5(4):769-775. doi: 10.1016/j.jseint.2021.04.010. eCollection 2021 Jul.
Right- and left-side throwers in baseball may have different shoulder conditions and throwing biomechanics. This study aimed to compare the passive range of motion, humeral torsion, and clinical findings between right- and left-handed throwers who sustained throwing shoulder injuries and confirm the differences in the characteristics between throwing sides.
A total of 52 pitchers diagnosed with throwing shoulder injuries were included in this study: 27 patients were right-side throwers (R group), and 25 were left-side throwers (L group). We measured the bilateral passive external and internal rotation angles in abduction position (ABIR) and total arc at their first visit. To assess posterior shoulder tightness, the internal rotation angles in forward flexion (FIR), and the abduction angle (AA) and horizontal flexion angle (HFA) without scapula motion were measured. The bilateral humeral torsion angles were also measured using ultrasonography. These values were compared between the participants' throwing and non-throwing sides and between the R and L groups' throwing sides. Furthermore, several physical findings in the shoulders were assessed, and the positive ratio was compared between the R and L groups.
On comparing the throwing and non-throwing sides, the R group had significantly greater external rotation angles in the abduction position and humeral torsion angle, and smaller ABIR, total arc, FIR, AA, and HFA in the throwing side, while the L group showed no significant differences, except for a smaller ABIR and larger HFA in the throwing side. On comparing the throwing side between the R and L groups, the R group had a smaller FIR, AA, and FHA than the L group. Regarding the physical findings, the posterior jerk test, Kim test, anterior and posterior drawer sign, sulcus sign, and scapular winging in the L group were significantly more positive than in the R group.
The range of motion and humeral torsions differed between the left- and right-side throwers, as did the pathology between their throwing sides. Clinicians should consider the possibility that the pathological condition differs between left- and right-side throwers.
棒球运动中的右投手和左投手可能存在不同的肩部状况和投掷生物力学特征。本研究旨在比较发生投掷肩损伤的右投手和左投手之间的被动活动范围、肱骨扭转情况及临床检查结果，并确认投掷侧之间特征上的差异。
本研究共纳入52名被诊断为投掷肩损伤的投手：27例患者为右投手（R组），25例为左投手（L组）。在他们首次就诊时，我们测量了双侧在外展位的被动外旋和内旋角度（ABIR）以及总活动弧度。为评估肩后部紧张度，测量了前屈位的内旋角度（FIR）、无肩胛骨活动时的外展角度（AA）和水平屈曲角度（HFA）。还使用超声测量了双侧肱骨扭转角度。将这些值在参与者的投掷侧和非投掷侧之间以及R组和L组的投掷侧之间进行比较。此外，评估了肩部的多项体格检查结果，并比较了R组和L组之间的阳性率。
在比较投掷侧和非投掷侧时，R组在投掷侧的外展位外旋角度和肱骨扭转角度明显更大，而ABIR、总活动弧度、FIR、AA和HFA更小，而L组除了投掷侧ABIR更小和HFA更大外，无显著差异。在比较R组和L组的投掷侧时，R组的FIR、AA和FHA比L组更小。关于体格检查结果，L组的后抽拉试验、金氏试验、前后抽屉征、沟征和肩胛翼状畸形比R组明显更阳性。
左右侧投手之间的活动范围和肱骨扭转情况不同，其投掷侧的病理状况也不同。临床医生应考虑到左右侧投手病理状况不同的可能性。
