Quantifying Bone and Skin Movement in the Residual Limb-Socket Interface of Individuals with Transtibial Amputation Using Dynamic Stereo X-Ray

下肢截肢（莱亚）的个体经常经历他们的下肢之间的相对运动。 残肢和假肢接受腔的垂直平移和轴向旋转等，会造成效率低下 从远端假体部件到残肢的动态载荷传递。这可能导致 严重的继发性后果，如疼痛、步态偏差和限制活动性的不适， 自治已经对骨和假肢接受腔之间的相对运动进行了评估， 但是，由于大多数研究，很少有关于动态的、在体的残肢-窝运动学的现有数据 使用非动态测试协议、静态测量或未经验证的表面进行 基于标记的动作捕捉系统。动态立体X射线（DSX）是一种先进的成像技术， 量化动态活动期间假肢接受腔内的3D骨移动和组织/内衬变形。 它可以实现功能性骨姿态（位置和方向）测量的亚毫米精度 通过将来自CT扫描的3D模型与来自双平面X射线视频的运动数据相结合， 在我们对残肢窝的复杂力学的理解上存在着实质性的差距 在动态活动期间的界面，限制了改善假体设计的能力。我们的四年目标 项目是开发分析工具，以量化动态，在体内运动学之间的残留 肢体和关节窝，以及残余组织/内衬变形的机制。为了验证灵敏度 我们将评估两种悬挂系统：高真空悬挂系统， (EV)和简单的抽吸我们假设有一种有效且高度准确的方法来量化动态 残肢和假肢接受腔之间的相互作用将足够敏感， 不同类型的假肢接受腔悬挂，这将进一步了解接受腔的生物力学 设计为此，研究人员将致力于以下目标：（1）优化DSX程序设置， 准确跟踪假肢接受腔、骨骼运动学和组织/内衬变形;（2）量化 在动力活动中，残余胫骨与假肢接受腔之间的相对运动;以及（3） 在动态活动期间测量假肢接受腔中的皮肤和衬里的变形。 为了实现这些目标，我们将首先采用尸体研究来优化无线电阵列的放置， 不透明珠和标记在插座，内衬和皮肤上，同时评估动态骨骼 移动和残留组织/内衬变形。将在迭代过程中使用5个尸体肢体， 开发最佳标记设置。将在每次DSX会话期间模拟站立相步态，以诱导骨 移动和皮肤/内衬变形。标记的数量和位置将在每次检查后进行评估。 会话，以优化标记放置，从而跟踪皮肤/内衬变形和骨骼移动。曾经是最佳的 识别标记设置后，21例经胫骨截肢的受试者将安装能够 通过EV和传统吸引器悬浮。受试者将经历4周的适应期，然后 在罗格斯大学的DSX设备上进行了测试。DSX将用于跟踪骨骼和皮肤/线性运动， 在3种动态活动中的两种悬挂技术：以自选速度在跑步机上行走，快速行走 (10%更快），以及步降运动。两种悬挂技术（主动电动车和 正常吸力）将通过量化剩余胫骨相对于 假体接受腔和量化内衬和接受腔-残体界面处的软组织变形。 通过使用分析工具对残余肢窝运动进行高度准确的体内评估， 可以提供重要的基础信息，以帮助开发新的方法和技术， 有可能减少继发性身体合并症和退行性变化的假体适配， 这是由于假体负荷传递不良的并发症造成的。

Individuals with lower extremity amputation (LEA) often experience relative motion between their residual limb and the prosthetic socket, such as vertical translation and axial rotation, which can cause inefficient dynamic load transmission from the distal prosthetic components to the residual limb. This can lead to significant secondary consequences, such as pain, gait deviations, and discomfort that limit mobility and autonomy. Assessments of the relative motion between the bone and the prosthetic socket have been performed, but there is little existing data on dynamic, in vivo residual limb-socket kinematics since most investigations have been performed using non-dynamic testing protocols, static measurements, or with unvalidated surface marker-based motion capture systems. Dynamic Stereo X-ray (DSX) is an advanced imaging technology that can quantify 3D bone movement and tissue/liner deformation inside a prosthetic socket during dynamic activities. It can achieve sub-millimeter accuracy of bone pose (position and orientation) measurement during functional movements by combining 3D models derived from CT scans with movement data from biplanar x-ray video. There is a substantial gap in our understanding of the complex mechanics of the residual limb-socket interface during dynamic activities that limit the ability to improve prosthetic design. Our 4-year goals for this project are to develop the analytical tools to quantify both the dynamic, in-vivo kinematics between the residual limb and socket, as well as the mechanism of residual tissue/liner deformation. In order to validate the sensitivity of this methodology to differences in socket suspension, we will evaluate 2 suspension systems: elevated vacuum (EV) and simple suction. We hypothesize that an efficient and highly accurate method to quantify the dynamic interaction between the residual limb and prosthetic socket will be sensitive enough to distinguish between different types of prosthetic socket suspension, which will further the biomechanical understanding of socket design. To do so, the investigators will address the following aims: (1) To optimize the DSX procedural setup for the accurate tracking of the prosthetic socket, skeletal kinematics, and tissue/liner deformation; (2) To quantify the relative motion between the residual tibia and the prosthetic socket during dynamic activities; and (3) To measure the deformation of the skin and liner in the prosthetic socket during dynamic activities. To address these aims, we will first employ a cadaver study to optimize the placement of an array of radio- opaque beads and markers on the socket, liner, and skin to simultaneously assess both dynamic skeletal movement and residual tissue/liner deformation. Five cadaver limbs will be utilized in an iterative process to develop an optimal marker setup. Stance phase gait will be simulated during each DSX session to induce bone movement and skin/liner deformation. The number and placement of markers will be evaluated after each session to refine the marker placement to track skin/liner deformation and skeletal movement. Once an optimal marker setup is identified, 21 subjects with transtibial amputation will be fit with a socket capable of being suspended via both EV and traditional suction. Subjects will undergo a 4-week acclimation period and then be tested at the DSX facility at Rutgers University. DSX will be utilized to track skeletal and skin/liner motion under both suspension techniques during 3 dynamic activities: treadmill walking at self-selected speed, fast walking (10% faster), and a step-down movement. The performance of the two suspension techniques (active EV and normal suction) will be tested by quantifying the 3D bone movement of the residual tibia with respect to the prosthetic socket and quantifying liner and soft tissue deformation at the socket-residuum interface. By using the analytical tools for a highly accurate, in-vivo assessment of residual limb-socket motion, we can provide vital foundational information to aid in the development of new methods and techniques to enhance prosthetic fit that have the potential to reduce secondary physical comorbidities and degenerative changes that result from complications of poor prosthetic load transmission.