GLENOHUMERAL JOINT STABILITY: ROLE OF THE CAPSULE

描述（由申请人提供）：肩关节是人体最常脱臼的关节。25岁以下肩关节脱位且单向前路不稳的患者中，高达90%的患者会出现难以诊断的复发，需要手术修复。手术治疗后，由于活动范围丧失、复发性不稳定、肩袖损伤或骨关节炎，20-25%的患者仍不能恢复正常功能。因此，研究工作需要更好地了解肩部被动稳定器的功能，以设计更好的诊断方案和手术入路，并改善长期预后。总的假设是，当修复后的盂肱囊能够在术后立即和长期内重现完整肩关节的功能时，肩关节手术的结果将得到改善。目前的肩部稳定器模型将盂肱囊描述为单轴元件（盂肱韧带）的集合。因此，本项目的目标是使用一种新型的盂肱前关节稳定性模型对盂肱囊的解剖和生物力学进行全面分析。这项工作将利用实验和计算相结合的方法来表征临床上相关关节位置的盂肱囊的结构和功能。本研究的三个具体目标是：1)量化盂肱囊后、前上、前下区域的局部多轴材料特性、微观结构形态和适当的本构模型随年龄和性别的变化；2)开发并验证临床相关关节位置的盂肱囊的个体有限元模型；3)在关节处于中外展、外展和收缩位的情况下，采用对象特定的有限元模型确定关节囊内的应力应变分布和受力。从这些创新和验证的模型中获得的定量数据是发展新的基于生物力学的策略的关键的第一步，用于改进肩关节脱位后的诊断程序和手术修复。这种方法也将作为最先进的分析其他关节胶囊在整个肌肉骨骼系统。

DESCRIPTION (provided by applicant): The shoulder is the most frequently dislocated joint of the body. Up to 90% of individuals less than 25 years of age that dislocate their glenohumeral joint and have unidirectional anterior instability suffer recurrence that is difficult to diagnose and necessitates surgical repair. Following surgical treatment, return to normal function remains inadequate with unsatisfactory results in 20-25% of patients due to loss of range of motion, recurrent instability, rotator cuff damage, or osteoarthritis. Therefore, research efforts to better understand the function of the passive stabilizers of the shoulder are needed to design better diagnostic protocols and surgical approaches as well as to improve the long-term outcome. The overall hypothesis is that the outcome of shoulder surgery will be improved when the repaired glenohumeral capsule can reproduce the function of the intact shoulder, both at the immediate post-operative periods and in the long-term. Current models of the shoulder stabilizers describe the glenohumeral capsule as a collection of uniaxial elements (glenohumeral ligaments). Therefore, the goal of this project is to perform a comprehensive analysis of the anatomy and biomechanics of the glenohumeral capsule using a novel model of anterior glenohumeral joint stability. The proposed work will utilize a combined experimental and computational approach to characterize the structure and function of the glenohumeral capsule in clinically relevant joint positions. The three Specific Aims of this proposal are: 1) quantify the local multi-axial material properties, microstructural morphology and appropriate constitutive model of the posterior, antero-superior and antero-inferior regions of the glenohumeral capsule as a function of age and gender; 2) develop and validate subject-specific finite element models of the glenohumeral capsule in clinically relevant joint positions; and 3) determine the stress and strain distribution as well as force in the glenohumeral capsule using subject-specific finite element models with the joint in mid-abduction, abduction and apprehension positions. The quantitative data obtained from these innovative and validated models is the first critical step towards the development of new biomechanically based strategies for improved diagnostic procedures and surgical repair following shoulder dislocation. This methodology will also serve as the state-of-the-art for analysis of other joint capsules throughout the musculoskeletal system.