Posterior Shoulder Capsules Are Thicker and Stiffer in the Throwing Shoulders of Healthy College Baseball Players

作者：Tetsuya Takenaga, Katsumasa Sugimoto, Hideyuki Goto, Masahiro Nozaki, Masaki Fukuyoshi, Atsushi Tsuchiya, Atsunori Murase, Tetsuya Ono, Takanobu Otsuka · 发表于：The American Journal of Sports Medicine · 年份：2015 · DOI：10.1177/0363546515608476 · 被引用次数：106 · 研究领域：Shoulder Injury and Treatment、Mechanics and Biomechanics Studies、Advanced Sensor Technologies Research

BACKGROUND: Posterior and posteroinferior capsules in the shoulder joints of throwing athletes have been reported to be thicker in throwing than nonthrowing shoulders, and this has a relationship to glenohumeral internal rotation deficit (GIRD). However, the stiffness of these thickened capsules has not been reported. Shear-wave ultrasound elastography is a new technology that can measure tissue elasticity quantitatively. HYPOTHESIS: The posterior and posteroinferior capsules are stiffer as well as thicker in the throwing shoulders of baseball players than in their nonthrowing shoulders. The thickness and elasticity of these capsules are inversely correlated with glenohumeral internal rotation. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Forty-five male college baseball players were examined. The thickness and elasticity of the posterior capsule beneath the infraspinatus and the posteroinferior capsule beneath the teres minor were measured using an ultrasonic device equipped with shear-wave elastographic technology. Glenohumeral internal rotation at 90° of shoulder abduction and humeral retrotorsion were also measured. RESULTS: The mean thickness and elasticity of the posterior capsule were significantly greater for the throwing compared with the nonthrowing shoulder (thickness: 1.34 vs 1.04 mm, respectively; elasticity: 40.0 vs 32.2 kPa, respectively; P < .001 for both). The mean thickness and elasticity of the posteroinferior capsule were also signif...