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加而增加。肩袖撕裂与肌肉体积和肩部力量减少、脂肪渗透、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，导致丧失独立性。有人建议，肩袖撕裂的人将采用补偿性运动或偏离预期运动，更多地依赖未受损的肌肉，以完成任务。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，有助于在健康衰老中看到的补偿。因此，随着年龄的增长，确定上肢代偿的必要性是至关重要的，以进一步探讨肩袖撕裂的老年人的功能变化。临床上，标准化的功能结果评分用于评估肩袖撕裂患者治疗后的功能能力和改善情况。然而，这些临床指标如何与ADL任务中的补偿有关还不是很清楚。为了更好地了解健康衰老、肩袖撕裂和功能能力之间的关系，有必要研究ADL的补偿，并确定参与这些运动的初级肌肉的力量和激活。这些目标将通过从健康和肩袖损伤的老年人身上获得6项ADL任务的运动学并为这些受试者开发特定于受试者的肌肉骨骼模型来实现。这些模型将被用来模拟ADL运动，以确定参与这些任务的肌肉的力和激活模式。具体地说，本研究将1)评估肩袖撕裂对肌肉体积、脂肪渗透和功能结果评分的影响，2)确定6种ADL在关节运动学上的差异，并评估贡献肌肉的活动范围、力量和激活，以及3)评估活动范围和肌肉力量对肌肉体积、脂肪渗透和功能结果评分的依赖。有兴趣研究老年人肩袖撕裂的代偿，以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导致代偿或无法完成功能任务的薄弱肌肉。这一信息将是 用于设计康复策略，以加强肌肉和改善受伤后的功能。这项工作的结果将为进一步了解老年人肩袖撕裂的损伤机制提供依据。随着美国人口继续老龄化，这一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.