Braun Benedikt J, Orth Marcel, Diebels Stefan, Wickert Kerstin, Andres Annchristin, Gawlitza Joshua, Bücker Arno, Pohlemann Tim, Roland Michael
University Hospital Tuebingen on Behalf of the Eberhard-Karls-University Tuebingen, Faculty of Medicine, BG Hospital Tuebingen, Tuebingen, Germany.
Department of Trauma, Hand and Reconstructive Surgery, Saarland University Hospital, Homburg, Germany.
Front Surg. 2021 Sep 29;8:749209. doi: 10.3389/fsurg.2021.749209. eCollection 2021.
Non-union rate after tibial fractures remains high. Apart from largely uncontrollable biologic, injury, and patient-specific factors, the mechanical fracture environment is a key determinant of healing. Our aim was to establish a patient-specific simulation workflow to determine the mechanical fracture environment and allow for an estimation of its healing potential. In a referred patient with failed nail-osteosynthesis after tibial-shaft fracture exchange nailing was performed. Post-operative CT-scans were used to construct a three-dimensional model of the treatment situation in an image processing and computer-aided design system. Resulting forces, computed in a simulation-driven workflow based on patient monitoring and motion capturing were used to simulate the mechanical fracture environment before and after exchange nailing. Implant stresses for the initial and revision situation, as well as interfragmentary movement, resulting hydrostatic, and octahedral shear strain were calculated and compared to the clinical course. The simulation model was able to adequately predict hardware stresses in the initial situation where mechanical implant failure occurred. Furthermore, hydrostatic and octahedral shear strain of the revision situation were calculated to be within published healing boundaries-accordingly the fracture healed uneventfully. Our workflow is able to determine the mechanical environment of a fracture fixation, calculate implant stresses, interfragmentary movement, and the resulting strain. Critical mechanical boundary conditions for fracture healing can be determined in relation to individual loading parameters. Based on this individualized treatment recommendations during the early post-operative phase in lower leg fractures are possible in order to prevent implant failure and non-union development.
胫骨骨折后的不愈合率仍然很高。除了很大程度上无法控制的生物学、损伤和患者特异性因素外，骨折的力学环境是愈合的关键决定因素。我们的目的是建立一个针对患者的模拟工作流程，以确定骨折的力学环境，并估计其愈合潜力。在一名因胫骨干骨折交锁髓内钉固定失败而转诊的患者中，进行了交锁髓内钉更换手术。术后CT扫描用于在图像处理和计算机辅助设计系统中构建治疗情况的三维模型。基于患者监测和运动捕捉的模拟驱动工作流程中计算出的合力，用于模拟交锁髓内钉更换前后的力学骨折环境。计算并比较了初始和翻修情况下的植入物应力，以及骨折块间移动、由此产生的流体静压和八面体剪应变与临床病程。模拟模型能够充分预测发生机械性植入物失败的初始情况下的硬件应力。此外，翻修情况下的流体静压和八面体剪应变经计算在已公布的愈合边界范围内，因此骨折顺利愈合。我们的工作流程能够确定骨折固定的力学环境，计算植入物应力、骨折块间移动和由此产生的应变。可以根据个体加载参数确定骨折愈合的关键力学边界条件。基于此，在小腿骨折术后早期阶段制定个性化的治疗建议成为可能，以防止植入物失败和不愈合的发生。
