Novel Methods to Assess Interfragmentary Motion: Quantifying a Critical Factor in Fracture Healing

项目总结/摘要 我们试图了解股骨远端骨折的手术固定和康复方案的变化 影响骨折处的力学环境，以及这反过来如何影响愈合。的概念 机械传导，其中物理力被转换成生物力学信号， 反应，与所有人类骨折的愈合有关。锁定钢板治疗股骨远端骨折 由于愈合并发症的发生率相对较高（高达32%）， 病例）和各种机械条件下的一系列治疗策略。面临的挑战 当试图提供稳定的，但生物友好的（即，促进继发性骨折愈合）固定. 该部位是所有长骨骨折的典型部位。虽然临床重要性 骨愈合中的机械传导-特别是穿过骨折部位的应变-已经被定性地 但缺乏量化数据。其具体机制尚未完全确定， 改善相关临床结果的进展停滞不前。缺乏定量的临床数据限制了我们 设计手术技术、植入物和康复方案以优化愈合结果的能力。 目前，该领域的一个主要障碍是无法评估骨折块间应变或临床上有用的评估方法。 代理人。]为了克服这一点，我们的目标是验证两种新的，非侵入性的，互补的方法， 量化临床[骨折部位运动]。方法1）将细化特定病例的计算模型， 最近接受股骨远端锁定钢板固定治疗的10名人类受试者的估计[骨折部位运动] 骨折方法2）双平面荧光透视将用于跟踪[近端和远端骨碎片]， 为这10名患者提供站立和行走服务。拟议的研究提供了两种互补的方法 在未来的转化研究中评估[骨折部位运动]。这些方法将通过尸体验证 试验.此外，测试队列中[骨折部位运动]的无负荷和负荷CT测量将[允许 体内验证]。计算建模提供了一种间接的、可扩展的方法来估计[骨折部位] 运动]，而双平面荧光透视将提供直接的体内评估。这两种方法将支持未来 涉及迄今为止无法验证的假设的翻译研究。这包括研究最佳固定 策略和康复方案，以及控制其他研究中混杂因素的能力 骨折愈合方面。这项创新工作旨在克服目前研究的局限性， 量化患者特异性[骨折部位运动]的补充方法，已被证明是一种 片段间应变的临床相关替代物。定量了解骨折部位的运动将 为直接针对机械传导的观察性研究和临床试验提供信息， 靶向骨折愈合的其他方面，以解释机械传导的潜在混杂效应。 此外，量化骨折部位运动是未来量化骨折块间运动的必要步骤。 应变。]这项转化研究开辟了多种机制和临床研究的途径， 通过降低骨折[延迟愈合和]骨不连的发生率来实现早期和长期的临床影响。 [The拟议的工作将支持未来的Merit Review资助一项前瞻性观察研究， 二次骨折愈合的固定策略和康复方案。

PROJECT SUMMARY/ABSTRACT We seek to understand how variations in surgical fixation and rehabilitation protocols for distal femur fractures impact the mechanical environment at the fracture and how this in turn influences healing. The concept of mechanotransduction, where physical forces are converted into biomechanical signals that guide cellular responses, is relevant to the healing of all human fractures. Distal femur fractures treated with locked plate fixation are an excellent model for study given a relatively high rate of healing complications (in up to 32% of cases) and a range of treatment strategies across a wide variety of mechanical conditions. The challenges faced when attempting to provide stable, yet biologically friendly (i.e., promoting secondary fracture healing) fixation at this site typify those encountered for all long bone fractures. Although the clinical importance of mechanotransduction in bone healing—in particular strain across a fracture site—has been qualitatively demonstrated, there is a lack of quantitative data. Its specific mechanisms are not fully characterized, and progress to improve related clinical outcomes [has been stagnant. A lack of quantitative clinical data limits our ability to design surgical techniques, implants, and rehabilitation protocols to optimize healing outcomes. Currently, a major obstacle in the field is an inability to assess interfragmentary strain or a clinically useful surrogate.] To overcome this, we aim to validate two novel, noninvasive, and complementary methods of quantifying clinical [fracture site motion]. Method 1) A case-specific computational model will be refined to estimate [fracture site motion] for 10 human subjects recently treated with locked plate fixation for a distal femur fracture. Method 2) Biplane fluoroscopy will be used to track [the proximal and distal bone fragments] during standing and walking for these same 10 patients. The proposed research provides two complementary methods of assessing [fracture site motion] in future translational research. These methods will be validated via cadaveric testing. Furthermore, unloaded and loaded CT measurements of [fracture site motion] in the test cohort will [allow in vivo validation]. Computational modeling provides an indirect, scalable method of estimating [fracture site motion] while biplane fluoroscopy will provide direct in vivo assessment. Both methods will support future translational research involving heretofore untestable hypotheses. This includes research into optimal fixation strategies and rehabilitation protocols, as well as the ability to control for confounding factors in studies of other aspects of fracture healing. This innovative work aims to overcome limitations in current research to develop two complementary methods of quantifying patient-specific [fracture site motion, which has been shown to be a clinically relevant surrogate for interfragmentary strain. A quantitative understanding of fracture site motion will inform observational studies and clinical trials directly targeting mechanotransduction and allow research targeting other aspects of fracture healing to account for a potential confounding effect of mechanotransduction. Further, quantifying fracture site motion is a necessary step toward future quantification of interfragmentary strain.] This translational study opens multiple avenues of mechanistic and clinical investigation with the potential for early and long-term clinical impact by decreasing the incidence of fracture [delayed union and] non-union. [The proposed work will support future Merit Review funding of a prospective observational study of optimizing fixation strategies and rehabilitation protocols for secondary fracture healing.]