Department of Orthopedic Surgery, Huashan Hospital, Fudan University, Shanghai, China.
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China.
Front Endocrinol (Lausanne). 2022 Aug 17;13:894383. doi: 10.3389/fendo.2022.894383. eCollection 2022.
This study was aimed to compare the material properties of heel pad between diabetes patients and healthy adults, and investigate the impact of compressive loading history and length of diabetes course on the material properties of heel pad.
The dual fluoroscopic imaging system (DFIS) and dynamic foot-ground contact pressure-test plate were used for measuring the material properties, including primary thickness, peak strain, peak stress, stiffness, viscous modulus and energy dissipation ratio (EDR), both at time zero and following continuous loading. Material properties between healthy adults and DM patients were compared both at time zero and following continuous weight bearing. After then, comparison between time-zero material properties and properties following continuous loading was performed to identify the loading history-dependent biomechanical behaviour of heel pad. Subgroup-based sensitivity analysis was then conducted to investigate the diabetes course (<10 years vs. ≥10 years) on the material properties of heel pad.
Ten type II DM subjects (20 legs), aged from 59 to 73 (average: 67.8 ± 4.9), and 10 age-matched healthy adults (20 legs), aged from 59 to 72 (average: 64.4 ± 3.4), were enrolled. Diabetes history was demonstrated to be associated with significantly lower primary thickness (t=3.18, p=0.003**), higher peak strain (t=2.41, p=0.021*), lower stiffness (w=283, p=0.024*) and lower viscous modulus (w=331, p<0.001***) at time zero, and significantly lower primary thickness (t=3.30, p=0.002**), higher peak strain (w=120, p=0.031*) and lower viscous modulus (t=3.42, p=0.002**) following continuous loading. The continuous loading was found to be associated with significantly lower primary thickness (paired-w=204, p<0.001***) and viscous modulus (paired-t=5.45, p<0.001***) in healthy adults, and significantly lower primary thickness (paired-w=206, p<0.001***) and viscous modulus (paired-t=7.47, p<0.001***) in diabetes group. No any significant difference was found when conducting the subgroup analysis based on length of diabetes course (<10 years vs. ≥10 years), but the regression analysis showed that the length of diabetes history was positively associated with the peak strain, at time zero (r=0.506, p<0.050) and following continuous loading (r=0.584, p<0.010).
Diabetes patients were found to be associated with decreased primary thickness and viscous modulus, and increased peak strain, which may contribute to the vulnerability of heel pad to injury and ulceration. Pre-compression history-dependent behaviour is observable in soft tissue of heel pad, with lowered primary thickness and viscous modulus.
本研究旨在比较糖尿病患者与健康成年人足跟垫的材料特性，并探讨压缩加载史和糖尿病病程对足跟垫材料特性的影响。
采用双荧光透视成像系统（DFIS）和动态足底接触压力测试板测量材料特性，包括初始厚度、峰值应变、峰值应力、刚度、粘性模量和能量耗散比（EDR），在零时刻和连续加载后进行测量。比较健康成年人和 DM 患者在零时刻和连续负重后的材料特性。然后，比较零时刻的材料特性和连续加载后的材料特性，以确定足跟垫的加载历史依赖性生物力学行为。然后进行基于亚组的敏感性分析，以研究糖尿病病程（<10 年与≥10 年）对足跟垫材料特性的影响。
纳入了 10 名 2 型 DM 患者（20 条腿），年龄 59 至 73 岁（平均 67.8±4.9），和 10 名年龄匹配的健康成年人（20 条腿），年龄 59 至 72 岁（平均 64.4±3.4）。结果表明，糖尿病病史与初始厚度降低（t=3.18，p=0.003**）、峰值应变升高（t=2.41，p=0.021*）、刚度降低（w=283，p=0.024*）和粘性模量降低（w=331，p<0.001**）有关，在零时刻；而在连续加载后，初始厚度降低（t=3.30，p=0.002**）、峰值应变升高（w=120，p=0.031*）和粘性模量降低（t=3.42，p=0.002**）更为明显。连续加载与健康成年人的初始厚度降低（配对-w=204，p<0.001**）和粘性模量降低（配对-t=5.45，p<0.001**）有关，与糖尿病组的初始厚度降低（配对-w=206，p<0.001**）和粘性模量降低（配对-t=7.47，p<0.001**）有关。但基于糖尿病病程的亚组分析（<10 年与≥10 年）并未发现任何显著差异，但回归分析表明，糖尿病病史与峰值应变呈正相关，无论是在零时刻（r=0.506，p<0.050）还是在连续加载后（r=0.584，p<0.010）。
糖尿病患者的足跟垫存在初始厚度和粘性模量降低，峰值应变升高的情况，这可能导致足跟垫更容易受伤和溃疡。足跟垫的软组织存在预压缩历史依赖性行为，表现为初始厚度和粘性模量降低。
