Institute of Biomedical Engineering and Technology, Academy for Engineering and Technology, Fudan University, 220 Handan Road, Shanghai, China.
Department of Orthopaedics, Huashan Hospital affiliated to Fudan University, 12 Middle Wulumuqi Road, Shanghai, China.
J Biomech. 2023 Aug;157:111744. doi: 10.1016/j.jbiomech.2023.111744. Epub 2023 Jul 28.
To accurately predict internal tissue loads for early diagnostics of diabetic foot ulcerations, a novel data-driven computational analysis was conducted. A dedicated dual fluoroscopic system was combined with a pressure mat to simultaneously characterize foot motions and soft tissue's material properties during gait. Finite element (FE) models of the heel pad of a diabetic patient were constructed with 3D trajectories of the calcaneus applied as boundary conditions to simulate gait events. The tensile and compressive stresses occurring in the plantar tissue were computed. Predictions of the layered tissue FE model with anatomically-accurate heel pad structures (i.e., fat and skin) were compared with those of the traditional lumped tissue (i.e., homogeneous) models. The influence of different material properties (patient-specific versus generic) on internal tissue stresses was also investigated. The results showed the peak tensile stresses in the layered tissue model were predominantly found in the skin and distributed towards the circumferential regions of the heel, while peak compressive stresses in the fat tissue-bone interface were up to 51.4% lower than those seen in the lumped models. Performing FE analyses at four different phases of walking revealed that ignorance of layered tissue structures resulted in an unphysiological increase of peak-to-peak value of stress fluctuation in the fat and skin tissue components. Thus, to produce more clinical-relevant predictions, foot FE models are suggested to include layered tissue structures of the plantar tissue for an improved estimation of internal stresses in the diabetic foot in gait.
为了准确预测糖尿病足溃疡的内部组织负荷，进行了一项新的数据驱动计算分析。专门的双荧光透视系统与压力垫相结合，以在步态过程中同时表征脚部运动和软组织的材料特性。应用跟骨的 3D 轨迹作为边界条件，构建了糖尿病患者跟垫的有限元（FE）模型，以模拟步态事件。计算了足底组织中的拉伸和压缩应力。将具有解剖学上准确的跟垫结构（即脂肪和皮肤）的分层组织 FE 模型的预测结果与传统的集中组织（即均匀）模型的预测结果进行了比较。还研究了不同材料特性（患者特定与通用）对内部组织应力的影响。结果表明，分层组织模型中的最大拉伸应力主要出现在皮肤中，并分布在脚跟的周向区域，而在脂肪组织-骨骼界面处的最大压缩应力比集中模型低 51.4%。在步行的四个不同阶段进行 FE 分析表明，忽略分层组织结构会导致脂肪和皮肤组织成分中的应力波动峰值到峰值值出现不生理的增加。因此，为了产生更具临床相关性的预测结果，建议将足底组织的分层组织结构纳入足部 FE 模型中，以提高对糖尿病患者在步态中内部应力的估计。
