Wolynski Jakob G, Ilić Milan M, Labus Kevin M, Notaroš Branislav M, Puttlitz Christian M, McGilvray Kirk C
Orthopaedic Bioengineering Research Laboratory, Departments of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, Colorado, USA.
School of Electrical Engineering, University of Belgrade, Belgrade, Serbia.
Ann Transl Med. 2022 May;10(9):510. doi: 10.21037/atm-21-5315.
Rapid prediction of adverse bone fracture healing outcome (e.g., nonunion and/or delayed union) is essential to advise adjunct therapies to reduce patient suffering and improving healing outcome. Radiographic diagnostic methods remain ineffective during early healing, resulting in average nonunion diagnosis times surpassing six months. To address this clinical deficit, we developed a novel diagnostic device to predict fracture healing outcome by noninvasive telemetric measurements of fracture bending stiffness. This study evaluated the hypothesis that our diagnostic antenna system is capable of accurately measuring temporal fracture healing stiffness, and advises the utility of this data for expedited prediction of healing outcomes during early (≤3 weeks) fracture recovery.
Fracture repair was simulated, in reverse chronology, by progressively destabilizing cadaveric ovine metatarsals (n=8) stabilized via locking plate fixation. Bending stiffness of each fracture state were predicted using a novel direct electromagnetic coupling diagnostic system, and results were compared to values from material testing (MT) methods. While direct calculation of fracture stiffness in a simplistic cadaver model is possible, comparable analysis of the innumerable permutations of fracture and treatment type is not feasible. Thus, clinical feasibility of direct electromagnetic coupling was explored by parametric finite element (FE) analyses (n=1,632 simulations). Implant mechanics were simulated throughout the course of healing for cases with variations to fracture size, implant type, implant structure, and implant material.
For all fracture states, stiffness values predicted by the direct electromagnetic coupling system were not significantly different than those quantified by MT methods [P=0.587, P=0.985, P=0.975; for comparing intact, destabilized, and fully fractured (FF) states; respectively]. In comparable models, the total implant deflection reduction (from FF to intact states) was less than 10% different between direct electromagnetic coupling measurements (82.2 µm) and FE predictions (74.7 µm). For all treatment parameters, FE analyses predicted nonlinear reduction in bending induced implant midspan deflections for increasing callus stiffness.
This technology demonstrates potential as a noninvasive clinical tool to accurately quantify healing fracture stiffness to augment and expedite healing outcome predictions made using radiographic imaging.
快速预测不良骨折愈合结果（如骨不连和/或延迟愈合）对于建议采用辅助治疗以减轻患者痛苦并改善愈合结果至关重要。在愈合早期，放射学诊断方法仍然无效，导致骨不连的平均诊断时间超过六个月。为了解决这一临床缺陷，我们开发了一种新型诊断设备，通过对骨折弯曲刚度进行非侵入式遥测测量来预测骨折愈合结果。本研究评估了我们的诊断天线系统能够准确测量骨折愈合过程中随时间变化的刚度这一假设，并探讨了该数据在早期（≤3周）骨折恢复期间加速预测愈合结果的实用性。
通过逐步破坏经锁定钢板固定的尸体绵羊跖骨（n = 8）来模拟骨折修复过程，模拟顺序与实际愈合过程相反。使用一种新型直接电磁耦合诊断系统预测每种骨折状态的弯曲刚度，并将结果与材料测试（MT）方法得到的值进行比较。虽然在简单的尸体模型中直接计算骨折刚度是可能的，但对骨折和治疗类型的无数种排列进行可比分析是不可行的。因此，通过参数有限元（FE）分析（n = 1632次模拟）探索了直接电磁耦合的临床可行性。针对骨折大小、植入物类型、植入物结构和植入物材料不同的情况，在整个愈合过程中模拟植入物力学。
对于所有骨折状态，直接电磁耦合系统预测的刚度值与MT方法量化的值无显著差异[P = 0.587、P = 0.985、P = 0.975；分别用于比较完整、不稳定和完全骨折（FF）状态]。在可比模型中，直接电磁耦合测量值（82.2 µm）与FE预测值（74.7 µm）之间，植入物总挠度减少量（从FF状态到完整状态）的差异小于10%。对于所有治疗参数，FE分析预测随着骨痂刚度增加，弯曲引起的植入物跨中挠度呈非线性减少。
这项技术显示出作为一种非侵入性临床工具的潜力，能够准确量化愈合骨折的刚度，以增强和加速使用放射影像学进行的愈合结果预测。
