Stability and instability of the glenohumeral joint: The role of shoulder muscles
Stability and instability of the glenohumeral joint: The role of shoulder muscles
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DOI：
10.1016/j.jse.2004.09.014
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发表时间：
2005-01-01
影响因子：
3
通讯作者：
McMahon, PJ
中科院分区：
文献类型：
--
作者：
Labriola, JE;Lee, TQ;McMahon, PJ
肩部肌肉有助于盂肱关节的灵活性和稳定性。为了改善肩部不稳定的治疗，我们重点关注肩部肌肉对临床相关位置盂肱关节稳定性的贡献。使用了计算模型和实验模型。盂肱关节的计算模型量化了中间范围和末端范围盂肱关节位置的主动肌肉力提供的稳定性。与中间位置相比，末端位置的合成关节力更向前，表明其对盂肱关节稳定性的贡献减弱。在极限位置，模拟的肩袖肌肉力量的增加往往会提高稳定性，而三角肌或胸大肌力量的增加往往会进一步降低稳定性。为了验证这些结果，使用模拟相关肩部肌肉的尸体模型来量化盂肱关节稳定性。当冈下肌活动减少时，压缩力也会减少。当胸大肌活动增加时，向前的力增加。如果向前的力增加或压缩力减少，盂肱关节的稳定性就会降低。然后使用该尸体模型来评估将关节置于外展、外旋和水平外展的牵制位置的效果。与我们的计算模型的结果一致，恐惧定位增加了向前的力。从这些模型中获得的知识随后被用来开发盂肱关节脱位的尸体模型。当模拟适当的肩部肌肉并包括被动的胸大肌时，由于强制捕获定位的机制而导致脱位。囊唇损伤的结果与体内观察到的相似。肩部肌肉力量通常是盂肱关节的强大稳定器，特别是在被动稳定器松弛时的中距离位置。然而，肌肉力量也会导致不稳定。某些肌肉力量会降低盂肱关节在末端位置的稳定性。我们发现主动和被动胸大肌的情况都是如此。更好地了解肌肉力量不仅对稳定性而且对不稳定的贡献，将改善肩部的康复方案，并被证明有助于治疗全身关节不稳定。
Shoulder muscles contribute to both mobility and stability of the glenohumeral joint. To improve treatments for shoulder instability, we focused on the contribution of the shoulder muscles to glenohumeral joint stability in clinically relevant positions. Both computational and experimental models were used. A computational model of the glenohumeral joint quantified stability provided by active muscle forces in both mid-range and end-range glenohumeral joint positions. Compared with mid-range positions, the resultant joint force at end-range positions was more anteriorly directed, indicating that its contribution to glenohumeral joint stability was diminished. In end-range positions, simulated increases in rotator cuff muscle forces tended to improve stability whereas increases in deltoid or pectoralis major muscle forces tended to further decrease stability. To validate these results, a cadaveric model, simulating relevant shoulder muscles, was used to quantify glenohumeral joint stability. When infraspinatus muscle activity was decreased, compressive forces decreased. When pectoralis major muscle activity was increased, anteriorly directed forces increased. If anteriorly directed forces increase or compressive forces decrease, stability of the glenohumeral joint decreases. This cadaveric model was then used to evaluate the effect of placing the joint in the apprehension position of abduction, external rotation, and horizontal abduction. Consistent with the results of our computational model, apprehension positioning increased anteriorly directed forces. Knowledge gained from these models was then used to develop a cadaveric model of glenohumeral joint dislocation. Dislocation resulted from the mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted that were similar to those observed in vivo. Shoulder muscle forces are usually powerful stabilizers of the glenohumeral joint, especially in mid-range positions when the Passive stabilizers are lax. However, muscle forces can contribute to instability as well. Certain muscle forces decrease glenohumeral joint stability in end-range positions. We found this to be the case with both active and passive pectoralis major forces. Improved understanding of the contribution of muscle forces not only toward stability but also toward instability will improve rehabilitation protocols for the shoulder and prove useful in the treatment of joint instability throughout the body.