A Multi-Scale Biomechanical model of the Infant Hip to Progress Innovation in Pediatric Hip Dysplasia Rehabilitation

该提案将首次通过实验和计算评估闭合复位治疗对发育性髋关节发育不良（DDH）婴儿的机械影响，从而开发创新的儿科康复干预措施，以缩短治疗时间并改善结局。DDH需要治疗的婴儿为2/1000。早期诊断和治疗与帕弗里克背带，一个70岁的解决方案，持有婴儿的臀部在一个弯曲和外展的位置，每天24小时，长达20周，是关键纠正DDH。然而，这种治疗有20%的失败率，需要手术干预。运动、肌肉活动和充分的关节接触是新生儿肌肉骨骼发育的关键，但还没有研究试图了解被动躺、主动踢和体位对婴儿髋关节发育的作用。我们的中心假设是，主动肌肉和髋关节的位置产生的帕弗里克安全带的可量化的组合诱导一个特定的，但目前未知的机械负荷在髋关节，在被动躺和主动运动，这有利于正确的髋关节发育。目的1将量化接受DDH治疗的婴儿的被动和主动髋关节力学。新诊断为DDH的婴儿将在Pavlik吊带治疗前后在我们的实验室进行2次生物力学测试。我们将使用活动传感器监测DDH婴儿的日常生活，以量化身体方向和被动与主动的时间。将在2年内的6次访视期间和治疗后跟踪临床结局。这一目标将有助于深入了解闭合复位治疗的患者选择，帮助确定理想的治疗时间，并导致定向治疗。目标2将评价Pavlik安全带对健康髋关节的机械载荷。由于佩戴Pavlik安全带时主动踢腿尝试或被动躺下导致的髋关节力的大小、方向和频率尚不清楚，这阻碍了DDH新疗法的开发。我们将使用传感器对Pavlik安全带进行仪表化，以评估在佩戴过程中施加到安全带上的力，从而了解安全带如何在活动和被动躺卧过程中对健康婴儿髋关节进行机械加载。目标3将建立婴儿髋关节闭合复位的计算模型。DDH婴儿的实验性肌肉和髋关节运动以及目标1中的患者特定几何形状以及目标2中主动运动和被动躺卧期间Pavlik安全带上诱导的力将作为肌肉骨骼和有限元模型的输入。这些婴儿髋关节闭合复位的计算模型将支持DDH治疗方法的改进。这项工作的预期成果是一个更完整的了解如何帕弗里克背带工程翻译被动和主动的力量，以婴儿髋关节。结果将提供有效的实验数据和计算模型，可以作为我们未来调查的基础，旨在为受DDH影响的婴儿和家庭开发创新的解决方案。

This proposal will be the first to experimentally and computationally assess the mechanical impact of closed reduction treatment on infants with developmental dysplasia of the hip (DDH), enabling the development of innovative pediatric rehabilitation interventions to decrease treatment duration and improve outcomes. DDH requires medical treatment in 2/1000 infants. Early diagnosis and treatment with a Pavlik harness, a 70-year-old solution that holds the infant’s hips in a flexed and abducted position for 24 hours/day for up to 20 weeks, are key to correcting DDH. However, the treatment has a 20% failure rate, requiring surgical intervention. Motion, muscle activity, and adequate joint contact are key to neonatal musculoskeletal development, yet no research has sought to understand the role of passive lying, active kicking, and body position on the development of the infant hip. Our central hypothesis is that a quantifiable combination of active muscles and hip position produced by the Pavlik harness induce a specific but currently unknown mechanical loading at the hip joint, during passive lying and active motion, which encourages correct hip development. Aim 1 will quantify passive and active hip mechanics of infants undergoing DDH treatment. Infants newly diagnosed with DDH will undergo 2 biomechanical test sessions in our laboratory before and after Pavlik harness treatment. We will monitor DDH infants in their daily life using activity sensors to quantify body orientation and time spent passive versus active. Clinical outcomes will be tracked during and after treatment during 6 visits over 2 years. This Aim will lend insight into patient selection for closed reduction treatment, help define the ideal treatment duration, and lead to directed therapies. Aim 2 will evaluate mechanical loading of the healthy hip by the Pavlik harness. The magnitude, direction, and frequency of forces at the hip due to active kicking attempts or passive lying while wearing the Pavlik harness are unknown, preventing the development of new therapies for DDH. We will instrument the Pavlik harness with sensors to evaluate the forces applied to the harness during wear to understand how the harness works to mechanically load the healthy infant hip during activity and passive lying. Aim 3 will develop computational models of the infant hip undergoing closed reduction. Experimental muscle and hip motion of DDH infants and patient-specific geometry from Aim 1 and forces induced on the Pavlik harness during active motion and passive lying from Aim 2 will serve as inputs to musculoskeletal and finite element models. These computational models of the infant hip joint undergoing closed reduction will support the development of improved DDH therapies. The expected outcome of this work is a more complete understanding of how the Pavlik harness works to translate passive and active forces to the infant hip. The results will provide valid experimental data and computational models that can serve as the basis for our future investigations aimed at developing innovative solutions for infants and families impacted by DDH.