Characterizing Patellofemoral Joint Stress Using Patient-Specific Models

描述（由申请人提供）： 髌股（PF）疼痛，也称为髌股综合征，被认为是涉及膝关节的最常见的肌肉骨骼疾病，也是25至40岁参加娱乐运动的成人中的头号肌肉骨骼诊断。就与退伍军人事务部人口的相关性而言，目前有260万年龄在25岁至40岁之间的退伍军人，如果他们参加娱乐体育活动，他们将面临风险。许多退伍军人的PF疼痛病例可能与服务有关。在第一次海湾战争的一组退伍军人中，13%被诊断为PF疼痛，在一项对步兵的单独研究中，髌股综合征是残疾索赔的头号原因。由于已知PF疼痛的慢性性，军事人员PF疼痛的患病率与VA相关。近75%被诊断为PF疼痛的患者在初次就诊后5年仍有疼痛，25%的PF疼痛患者的症状持续长达20年。因此，在现役期间发展PF疼痛的相当大比例的军事人员将继续有症状，因为这些人过渡到退伍军人状态。治疗患有PF疼痛的退伍军人的费用是巨大的。根据最新的患病率和成本数据，我们估计，在诊断后的第一年内，与退伍军人PF疼痛治疗相关的医疗费用为15亿美元。相比之下，治疗伊朗和阿富汗退伍军人的医疗费用目前估计为每年20亿美元。 在一篇关于髌股关节疼痛的社论中，一位临床医生指出，治疗通常基于“关于髌股关节生物力学的传统信念”，并且“这种方法的临床结果往往不尽如人意”。作为使用传统信念而不是坚实的循证医学的可能理由，一个著名的研究小组表示，“PF疼痛的病因，发病机制和推荐的治疗方法仍不清楚。“这些说法在今天和十年前一样正确。 近年来，人们逐渐认识到，量化PF关节内的组织应力可能会为PF疼痛的一个潜在原因提供新的见解。检验这种压力假设的一个关键障碍是缺乏精心设计的研究，其中将PF疼痛受试者组与健康、年龄和性别匹配的无痛对照组之间PF关节内的压力进行比较。反过来，进行精心设计的研究的一个重大障碍是缺乏对各组受试者组织应力的平均值和标准差的了解。如果不能很好地估计相关人群中组织应力的变化，就不可能根据假设特异性功效计算设计稳健的研究。 由于组织应力不能在体内直接测量，因此必须使用基于解剖学和生理学模型的计算分析来计算应力。在过去的七年里，我们的研究团队积累了一个关于PF疼痛受试者的大型队列的全面数据集。迄今为止，我们已经获取了50名PF疼痛受试者和15名健康对照者在直立负重期间的高级成像数据，以及沿着的运动捕获数据和EMG数据。这些数据已被删除，可供进一步处理。我们还开发了一个建模管道，以促进从成像和肌肉活动数据创建高保真有限元模型。拟议初步研究的目标是：1）通过确定有和无PF疼痛受试者PF关节中组织应力的平均值和标准差，消除进展的关键障碍; 2）确定组织应力对模型输入参数不确定性的敏感性。我们提出的试点研究的结果将使未来的研究，重点是组织应力的作用，作为PF疼痛的潜在原因和新的干预措施，可能会改变组织应力和缓解疼痛的稳健设计。

DESCRIPTION (provided by applicant): Patellofemoral (PF) pain, also called patellofemoral syndrome, is recognized as the most common musculoskeletal condition involving the knee and the number one musculoskeletal diagnosis among adults between the ages of 25 and 40 years who participate in recreational sports. In terms of relevance to the VA population, there are currently 2.6M veterans between the ages of 25 and 40 who are at risk if they participate in recreational sports. Many cases of PF pain in veterans may be service connected. In a group of veterans of the first Gulf War, 13% were diagnosed with PF pain and in a separate study of infantry soldiers, patellofemoral syndrome was the number one cause of disability claims. The prevalence of PF pain in military personnel is relevant to the VA because of the known chronicity of PF pain. Nearly 75% of patients diagnosed with PF pain still experience pain five years following initial presentation and 25% of patients with PF pain have symptoms that persist for up to 20 years. Thus, a substantial proportion of military personnel who develop PF pain during active service will continue to have symptoms as those individuals transition to veteran status. The cost of treating veterans with PF pain is dramatic. Based on newly available prevalence and cost data, we estimate that the medical costs associated with the treatment of PF pain in veterans in just the first year following diagnosis is $1.5B. By comparison, the medical cost for treating Iran and Afghanistan veterans is currently estimated to be $2.0B per year. In an editorial on patellofemoral pain, one clinician noted that treatment is often based on "traditional beliefs regarding patellofemoral biomechanics" and "all too often, the clinical results from this type of approach are less than desirable". As a possible justification for the use of traditional beliefs rather than solid evidence-based medicine, one prominent research group stated "the aetiology, pathogenesis, and recommended treatment [of PF pain] remain unclear." These statements are as true today as they were a decade ago. In recent years there has been an evolving awareness that quantifying the tissue stresses within the PF joint may provide new insight into one potential cause of PF pain. A critical barrier to testing this stress hypothesis is an absence of well-designed studies in which stresses within the PF joint are compared between groups of subjects with PF pain and healthy, age and gender-matched pain-free controls. In turn, a significant obstacle to performing well-designed studies is a lack of knowledge of the means and the standard deviations, of the tissue stresses for the respective groups of subjects. Without having a good estimate of the variation in tissue stress across a relevant population it is impossible to design a robust study based on hypothesis- specific power calculations. Since tissue stresses cannot be directly measured in vivo, computational analysis must be used to calculate stress using anatomical and physiological-based models. Over the past seven years, our research team has accumulated a comprehensive data set on a large cohort of PF pain subjects. To date we have acquired advanced imaging data during upright weight-bearing, along with motion capture data and EMG data for fifty subjects with PF pain and for fifteen healthy controls. These data have been de-identified and are available for further processing. We have also developed a modeling pipeline to facilitate the creation of high- fidelity finite element models from imaging and muscle activity data. The goals of the proposed pilot study are: 1) to eliminate a critical barrier to progress by determining the means and standard deviations of the tissue stresses in the PF joint in subjects with and without PF pain; and 2) to determine the sensitivity of the tissue stresses to uncertainties in model input parameters. The results of our proposed pilot study will enable the robust design of future studies that focus on the role of tissue stresses as a potential cause of PF pain and on novel interventions that might alter tissue stresses and alleviate pain.