Effect of Prosthetic Foot-Ankle Stiffness on Amputee Function

描述(由申请人提供)： 项目摘要许多下肢截肢者戴着假肢，通过弹性龙骨的关节来储存和释放能量。这些能量储存和回流(ESAR)脚的功能是为曾经由跨越脚踝关节的肌肉提供的推进提供机械能量。临床医生很清楚，足部僵硬强烈影响截肢者的步态机制，并根据体重和自我报告的活动水平，为Esar足部开出制造商确定的僵硬水平。然而，几乎没有客观的生物力学数据来指导一种僵硬水平与另一种僵硬水平的对比，截肢者与非截肢者相比，继续经历着显著的生物力学和代谢性步态缺陷，并经常由于肢体负荷异常而在完整和残肢发生继发性肌肉骨骼疾病。我们相信，如果了解截肢者的ESAR特性与生物力学和代谢反应之间的关系，这些不利结果中的许多都可以得到缓解。然而，到目前为止，还没有研究系统地改变假肢足僵硬的广泛范围来确定这些关系。另一个因素是，到目前为止，大多数评估Esar脚有效性的研究都是在直线行走过程中进行的。然而，非矢状面活动，如旋转，在日常生活中很普遍，并为Esar脚创造了一套不同的设计要求，但尚未进行评估。为了解决这一重要的临床问题，本研究的总体目标是系统地研究假肢足踝僵硬对截肢者直线行走和转身时步态表现的影响，以确定这种关系并探索其作为预测性处方工具的用途。这项拟议工作的一个独特之处是使用快速原型系统快速制造具有广泛僵硬特性的患者专用假肢。具体目标1将通过对20名单侧经胫骨截肢者(n=20)在直线行走过程中佩戴5种不同僵硬程度的假肢进行人体实验，确定矢状面足部僵硬对截肢者步态的影响。我们将使用快速成型技术来制造与每个受试者自己的临床处方假体和其他四个假体(125%和150%或多或少僵硬)的矢状面和冠状面上的僵硬特性相匹配的足部。每只脚的特定于患者的特性将使用机器人步态模拟器精确确定。在僵硬条件下，每个受试者将在假体上沿直线行走，以测试特定的假设，这些假说将矢状面僵硬与步态力学和代谢成本的预期变化联系起来。具体目标2将使用类似的实验设计和方法来确定冠状平面足部僵硬对截肢者步态的影响。单侧经胫骨截肢者(n=20)在直线行走和沿曲线行走时，将佩戴5种不同冠状面僵硬水平(按规定和125%和150%或多或少僵硬)的假肢。来自第二个实验的数据将使假设检验能够将冠状面僵硬与步态力学的预期变化联系起来。我们假设截肢者的活动能力可以通过优化他们的假肢在矢状面和冠状面上的僵硬来改善。这项研究将提供对假肢特性如何影响截肢者步态的透彻了解，并帮助我们实现为临床开发预测性处方工具的长期目标，从而提高截肢者的灵活性、独立性和生活质量。 公共卫生相关性： 拟议工作与退伍军人事务部患者护理任务的项目叙述退伍军人外科医生每年进行3000至5000例下肢截肢手术(Mayfield等人，2000年)。我国糖尿病和血管疾病人口的老龄化表明，这一数字只会增加。此外，目前伊拉克和阿富汗的军事冲突正在导致更多的创伤病因截肢者；这些人将在未来多年依赖退伍军人管理局。开发改进退伍军人康复护理的创新方法是退伍军人管理局的优先事项。这项研究将在临床上对假肢脚踝特性如何影响截肢者的步态产生临床相关的理解。我们相信，通过这项研究传播的知识将使退伍军人下肢截肢者的健康、独立性、就业、娱乐和生活质量得到实质性改善。

DESCRIPTION (provided by applicant): Project Summary Many lower limb amputees wear prosthetic feet that store and release energy through articulation of an elastic keel. The function of these energy storage and return (ESAR) feet are to provide mechanical energy for propulsion that was once provided by the muscles crossing the ankle joint. Clinicians are well aware that foot stiffness strongly influences the mechanics of amputee gait and prescribe ESAR feet with manufacturer-identified stiffness levels based on body weight and self-reported activity level. However, very little objective biomechanical data exists to guide the prescription of one stiffness level versus another and amputees continue to experience significant biomechanical and metabolic gait deficits relative to non-amputees and often develop secondary musculoskeletal disorders in both the intact and residual limbs due to abnormal limb loading. We believe many of these adverse results can be mitigated if the relationships between ESAR properties and the biomechanical and metabolic response of amputees are understood. However, to date no study has systematically varied prosthetic foot stiffness across a wide range of values to identify these relationships. Another contributing factor is that to date the majority of research evaluating the effectiveness of ESAR feet has been performed during straight line walking. However, non-sagittal plane activities such as turning are prevalent in daily living and create a different set of design requirements for ESAR feet that has yet to be evaluated. To address this important clinical problem, the overall goal of this research is to perform a systematic study of the influence of prosthetic foot-ankle stiffness on amputee gait performance during straight-line walking and turning to define this relationship and explore its use as a predictive prescription tool.. A unique element of the proposed work is the use of a rapid prototyping system to quickly fabricate patient- specific prosthetic feet with a wide range of stiffness properties. Specific Aim 1 will identify the effects of sagittal plane foot stiffness on amputee gait through a human subject experiment with unilateral transtibial amputees (n=20) wearing prosthetic feet with five different stiffness levels during straight-line walking. We will use rapid prototyping techniques to fabricate feet that match the stiffness properties in both the sagittal and coronal planes of each subject's own clinically prescribed prosthesis and four others (125% and 150% more or less stiff). The patient-specific properties of each foot will be precisely determined using a robotic gait simulator. Blinded to stiffness conditions, each subject will walk in a straight line on the prostheses to test specific hypotheses relating sagittal plane stiffness to expected changes in gait mechanics and metabolic cost. Specific Aim 2 will identify the effects of coronal plane foot stiffness on amputee gait using a similar experimental design and methods. Unilateral transtibial amputees (n=20) will wear prosthetic feet with five different coronal plane stiffness levels (as-prescribed and 125% and 150% more or less stiff) during straight-line walking and while walking along a curved path. Data from this second experiment will enable hypothesis testing relating coronal plane stiffness to expected changes in gait mechanics. We hypothesize that amputee mobility can be improved by optimizing the stiffness of their prosthetic feet in both the sagittal and coronal planes. This study will provide a thorough understanding of how prosthetic foot properties effect amputee gait and help us achieve our long-term goal of developing predictive prescription tools for the clinic that will result in greater amputee mobility, independence, and quality of life. PUBLIC HEALTH RELEVANCE: Project Narrative Relevance of the Proposed Work to the VA Patient Care Mission VA surgeons perform between 3000 and 5000 lower limb amputation procedures each year (Mayfield et al., 2000). The aging of our nation's diabetic and dysvascular populations suggest this number will do nothing but grow. Further, the current military conflicts in Iraq and Afghanistan are resulting in additional amputees of traumatic etiology; a population who will rely on the VA for years to come. Developing innovative approaches to improving Veteran rehabilitative care is a VA priority. This research will produce a clinically-relevant understanding of how prosthetic foot-ankle properties effect lower limb amputee gait. We believe that the knowledge disseminated from this research will lead to a substantial improvement of the health, independence, employment, recreation, and quality of life of Veteran lower limb amputees.