Luyckx Thomas, Verstraete Matthias, De Roo Karel, De Waele Wim, Bellemans Johan, Victor Jan
Department of Orthopaedic Surgery & Traumatology, University Hospitals Leuven, Weligerveld 1, Pellenberg, 3212, Belgium.
Department of Orthopaedic Surgery & Traumatology, University Hospital Gent, Gent, Belgium.
J Exp Orthop. 2014 Dec;1(1):7. doi: 10.1186/s40634-014-0007-8. Epub 2014 Jun 26.
Determining the mechanical behaviour of tendon and ligamentous tissue remains challenging, as it is anisotropic, non-linear and inhomogeneous in nature.
In this study, three-dimensional (3D) digital image correlation (DIC) was adopted to examine the strain distribution in the human Achilles tendon. Therefore, 6 fresh frozen human Achilles tendon specimens were mounted in a custom made rig for uni-axial loading. 3D DIC measurements of each loading position were obtained and compared to 2 linear variable differential transformers (LVDT's).
3D DIC was able to calculate tendon strain in every region of all obtained images. The scatter was found to be low in all specimens and comparable to that obtained in steel applications. The accuracy of the 3D DIC measurement was higher in the centre of the specimen where scatter values around 0.03% strain were obtained. The overall scatter remained below 0.3% in all specimens. The spatial resolution of 3D DIC on human tendon tissue was found to be 0.1 mm(2). The correlation coefficient between the 3D DIC measurements and the LVDT measurements showed an excellent linear agreement in all specimens (R(2) = 0.99). Apart from the longitudinal strain component, an important transverse strain component was revealed in all specimens. The strain distribution of both components was of a strongly inhomogeneous nature, both within the same specimen and amongst different specimens.
DIC proved to be a very accurate and reproducible tool for 3D strain analysis in human tendon tissue.
确定肌腱和韧带组织的力学行为仍然具有挑战性，因为其本质上具有各向异性、非线性和不均匀性。
在本研究中，采用三维（3D）数字图像相关（DIC）技术来检测人体跟腱中的应变分布。因此，将6个新鲜冷冻的人体跟腱标本安装在定制的装置中进行单轴加载。获取每个加载位置的3D DIC测量值，并与2个线性可变差动变压器（LVDT）进行比较。
3D DIC能够计算所有获取图像中每个区域的肌腱应变。发现所有标本中的离散度都很低，与在钢铁应用中获得的结果相当。在标本中心，3D DIC测量的精度更高，在该区域获得的应变离散值约为0.03%。所有标本中的总体离散度均保持在0.3%以下。发现3D DIC在人体肌腱组织上的空间分辨率为0.1 mm²。3D DIC测量值与LVDT测量值之间的相关系数在所有标本中均显示出极佳的线性一致性（R² = 0.99）。除纵向应变分量外，所有标本中均显示出重要的横向应变分量。在同一标本内和不同标本之间，这两个分量的应变分布均具有很强的不均匀性。
DIC被证明是用于人体肌腱组织三维应变分析的非常准确且可重复的工具。
