Effect of Posteroinferior Capsule Tightness on Contact Pressure and Area Beneath the Coracoacromial Arch During Pitching Motion
Effect of Posteroinferior Capsule Tightness on Contact Pressure and Area Beneath the Coracoacromial Arch During Pitching Motion
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DOI：
10.1177/0363546509350074
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发表时间：
2010-03-01
影响因子：
4.8
通讯作者：
An, Kai-Nan
中科院分区：
文献类型：
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作者：
Muraki, Takayuki;Yamamoto, Nobuyuki;An, Kai-Nan
背景：后下关节囊的紧密性被认为是棒球投手内旋丧失的原因。虽然后囊和肩峰下撞击之间的关系已被公认，这种关系在棒球投球motion.Hypothesis：接触压力在棒球投球运动增加后囊tight.Study设计：对照实验室study.Methods：八个新鲜冷冻的肩膀被使用。在定制设计的能够进行6个自由度运动的肩部实验装置上测量喙肩弓上的峰值接触压力和面积。同时，从不同角度观察喙肩弓和肱骨的峰值压力部位。通过在6点至8点的区域折叠囊来模拟后下囊的紧密性。静态测试位置与俯仰运动的早期翘起、晚期翘起、加速、减速和后续阶段相关。结果：后续阶段的峰值接触压力（0.63 +/- 0.50 MPa）随后下囊紧密度（1.00 +/- 0.65 MPa）显著增加（P = 0.014）。此外，随访期喙肩韧带的接触面积（0.98 +/- 0.67 cm（2））随着后下关节囊的紧密度（1.47 +/- 0.91 cm（2））显著增加（p <0.001）。峰值接触压力的位置在两种条件之间没有变化。结论：我们的研究结果表明，后下关节囊紧密度导致肩峰下弓下的接触压力较高，接触面积增加，特别是在后续阶段的喙肩韧带上。临床相关性：这种紧绷可能会增加俯仰过程中肩峰下接触，从而影响肩袖及其周围组织损伤的风险。
Background: Tightness of the posteroinferior capsule is assumed to be the cause of internal rotation loss in baseball pitchers. Although the relationship between posterior capsule and subacromial impingement has been recognized, this relationship during the baseball-pitching motion is unclear.Hypothesis: Contact pressure during baseball-pitching motion increases with posterior capsule tightness.Study Design: Controlled laboratory study.Methods: Eight fresh-frozen shoulders were used. The peak contact pressure and area on the coracoacromial arch were measured on a custom-designed shoulder experimental device capable of 6 degrees of freedom motion. Simultaneously, the sites of peak pressure on the coracoacromial arch and humerus were observed from various angles. The posteroinferior capsule tightness was simulated by plicating the capsule in the region from 6 to 8 o'clock. The static testing positions correlated to the early cocking, late cocking, acceleration, deceleration, and follow-through phases of the pitching motion.Results: The peak contact pressure during the follow-through phase (0.63 +/- 0.50 MPa) significantly increased with posteroinferior capsule tightness (1.00 +/- 0.65 MPa) (P = .014). Additionally, the contact area on the coracoacromial ligament during the follow-through phase (0.98 +/- 0.67 cm(2)) significantly increased with posteroinferior capsule tightness (1.47 +/- 0.91 cm(2)) (p < .001). The site of the peak contact pressure did not change between the 2 conditions.Conclusion: Our findings demonstrate that posteroinferior capsule tightness leads to higher contact pressure under the subacromial arch and increased contact area, particularly on the coracoacromial ligament during the follow-through phase.Clinical Relevance: This tightness may affect risk of injury of the rotator cuff and its surrounding tissues by increasing subacromial contact during pitching.