Muscle function and compensation following rotator cuff tear in older adults

描述（由申请人提供）：大约20-50%的老年人（年龄> 65岁）患有肩袖撕裂，这个数字随着年龄的增长而增加。肩袖撕裂与肌肉体积和肩部力量减少、脂肪浸润、活动范围减少和活动受限有关。这些缺陷会影响老年人进行日常生活活动（ADL）的能力，导致独立性丧失。有人认为，肩袖撕裂的个体将采用补偿运动或偏离期望的运动，更依赖于未受损的肌肉来完成任务。然而，衰老过程会引起骨骼肌的变化，这可能会影响运动协调和肌肉力量，有助于健康衰老中的补偿。因此，有必要确定上肢代偿随年龄增长的必要程度，以进一步探讨肩袖撕裂老年人的功能变化。临床上，标准化功能结局评分用于评估肩袖撕裂患者治疗后的功能能力和改善。然而，还没有很好地理解这些临床指标如何与ADL任务中的补偿相关。为了更好地了解健康老龄化、肩袖撕裂和功能能力之间的关系，有必要研究ADL中的补偿，并确定有助于这些运动的主要肌肉的强度和激活。这些目标将通过从健康和肩袖损伤的老年人中获得6项ADL任务的运动学并为这些受试者开发受试者特定的肌肉骨骼模型来实现。这些模型将用于模拟ADL运动，以识别有助于这些任务的肌肉的力和激活模式。具体来说，本研究将1）评估肩袖撕裂对肌肉体积、脂肪浸润和功能结局评分的影响，2）确定6种ADL的关节运动学差异，并评估活动范围以及贡献肌肉的力量和激活，以及3）评估活动范围和肌肉力量对肌肉体积、脂肪浸润和功能结局评分的依赖性。研究老年人肩袖撕裂后的代偿功能有助于进一步了解这种损伤的功能后果。这项研究的长期目标是确定有助于补偿或无法完成功能任务的薄弱肌肉。此信息将 用于设计康复策略以增强肌肉并改善受伤后的功能。这项工作的结果将提供进一步了解的机制，在老年人的损伤与肩袖撕裂。随着美国人口继续老龄化，这些信息可能会产生重大影响。

DESCRIPTION (provided by applicant): Approximately 20-50% of older adults (age > 65 years) are living with a rotator cuff tear, and this number increases with advanced age. A rotator cuff tear is associated with decreased muscle volume and shoulder strength, fatty infiltration, reduced range of motion, and limited mobility. These deficits can impact older adults ability to perform activities of daily living (ADLs), resulting in a loss of independence. It has been suggested that individuals with a torn rotator cuff will employ compensatory movements or deviations from the desired movement with a greater reliance on unimpaired muscles, to complete tasks. However, the aging process induces changes to skeletal muscle which may affect motor coordination and muscle strength, contributing to compensation seen in healthy aging. Therefore, it is essential to identify the extent to which upper limb compensation is necessary with age to further explore the functional changes occurring in older adults with a rotator cuff tear. Clinically, standardized functional outcome scores are used to assess functional ability and improvements following treatment for patients with a rotator cuff tear. However, it is not well understood how these clinical metrics relate to compensation in ADL tasks. To better understand the relationships between healthy aging, rotator cuff tears, and functional ability, it is necessary investigate compensation in ADLs and identify the strength and activation of primary muscles contributing to these movements. These objectives will be accomplished by obtaining kinematics for 6 ADL tasks from healthy and rotator cuff injured older adults and developing subject-specific musculoskeletal models for these subjects. These models will be used to simulate the ADL movements to identify the forces and activation patterns of muscles contributing to these tasks. Specifically, this study will 1) evaluate the effet of rotator cuff tear on muscle volume, fatty infiltration and functional outcome scores, 2) identif differences in joint kinematics for 6 ADLs and evaluate the range of motion, and force and activation of contributing muscles, and 3) evaluate the dependence of range of motion and muscle force on muscle volume, fatty infiltration, and functional outcome score. It is of interest o study compensation in older adults with a rotator cuff tear to further understand the functional consequences of this injury. The long term goal of this study is to identify weak muscles that contribute to compensation or the inability to complete a functional task. This information will be used to design rehabilitation strategies to strengthen muscles and improve function after injury. The outcomes of this work will provide further understanding of the mechanism of injury in older adults with a rotator cuff tear. This information may have a substantial impact as the US population continues to age.