Musculoskeletal Research Center, Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, 405 Center for Bioengineering, 300 Technology Dr., Pittsburgh, PA 15219, USA.
J Appl Physiol (1985). 2010 Jun;108(6):1711-8. doi: 10.1152/japplphysiol.01175.2009. Epub 2010 Apr 15.
Surgical repair of the glenohumeral capsule after dislocation ignores regional boundaries of the capsule and is not sex specific. However, each region of the capsule functions to stabilize the joint in different positions, and differences in joint laxity between men and women have been found. The objectives of this research were to determine the effects of region (axillary pouch and posterior capsule) and sex on the material properties of the glenohumeral capsule. Boundary conditions derived from experiments were used to create finite-element models that applied tensile deformations to tissue samples from the capsule. The material coefficients of a hyperelastic constitutive model were determined via inverse finite-element optimization, which minimized the difference between the experimental and finite-element model-predicted load-elongation curve. These coefficients were then used to create stress-stretch curves representing the material properties of the capsule regions for each sex in response to uniaxial extension. For the axillary pouch, the C1 (men: 0.28+/-0.39 MPa and women: 0.23+/-0.12 MPa) and C2 (men: 8.2+/-4.1 and women: 7.7+/-3.0) material coefficients differed between men and women by only 0.05 MPa and 0.5, respectively. Similarly, the posterior capsule coefficients differed by 0.15 MPa (male: 0.49+/-0.26 MPa and female: 0.34+/-0.20 MPa) and 0.6 (male: 7.8+/-2.9 and female: 7.2+/-3.0), respectively. No differences could be detected in the material coefficients between regions or sexes. As a result, surgeons may not need to consider region- and sex-specific surgical repair techniques. Furthermore, finite-element models of the glenohumeral joint may not need region- or sex-specific material coefficients when using this constitutive model.
肩关节囊的脱位后修复忽略了囊的区域边界，并且不具有性别特异性。然而，囊的每个区域在不同的位置都具有稳定关节的功能，并且已经发现男性和女性之间的关节松弛度存在差异。本研究的目的是确定区域（腋窝袋和后囊）和性别对肩关节囊材料特性的影响。从实验中得出的边界条件用于创建有限元模型，这些模型对来自囊的组织样本施加拉伸变形。超弹性本构模型的材料系数通过逆有限元优化确定，该优化最小化了实验和有限元模型预测的载荷-伸长曲线之间的差异。然后，使用这些系数创建了表示每个性别囊区域的材料特性的应力-应变曲线，以响应单轴拉伸。对于腋窝袋，C1（男性：0.28+/-0.39 MPa 和女性：0.23+/-0.12 MPa）和 C2（男性：8.2+/-4.1 和女性：7.7+/-3.0）的材料系数在男性和女性之间仅相差 0.05 MPa 和 0.5。同样，后囊的系数相差 0.15 MPa（男性：0.49+/-0.26 MPa 和女性：0.34+/-0.20 MPa）和 0.6（男性：7.8+/-2.9 和女性：7.2+/-3.0）。在区域或性别之间，无法检测到材料系数的差异。因此，外科医生可能不需要考虑区域和性别特异性的手术修复技术。此外，当使用这种本构模型时，肩关节的有限元模型可能不需要区域或性别特异性的材料系数。
