Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, 14424, Potsdam, Germany.
Biomech Model Mechanobiol. 2012 Jan;11(1-2):147-60. doi: 10.1007/s10237-011-0299-x. Epub 2011 Mar 24.
During secondary bone healing, different tissue types are formed within the fracture callus depending on the local mechanical and biological environment. Our aim was to understand the temporal succession of these tissue patterns for a normal bone healing progression by means of a basic mechanobiological model. The experimental data stemmed from an extensive, previously published animal experiment on sheep with a 3 mm tibial osteotomy. Using recent experimental data, the development of the hard callus was modelled as a porous material with increasing stiffness and decreasing porosity. A basic phenomenological model was employed with a small number of simulation parameters, which allowed comprehensive parameter studies. The model distinguished between the formation of new bone via endochondral and intramembranous ossification. To evaluate the outcome of the computer simulations, the tissue images of the simulations were compared with experimentally derived tissue images for a normal healing progression in sheep. Parameter studies of the threshold values for the regulation of tissue formation were performed, and the source of the biological stimulation (comprising e.g. stem cells) was varied. It was found that the formation of the hard callus could be reproduced in silico for a wide range of threshold values. However, the bridging of the fracture gap by cartilage on the periosteal side was observed only (i) for a rather specific choice of the threshold values for tissue differentiation and (ii) when assuming a strong source of biological stimulation at the periosteum.
在二次骨愈合过程中，根据局部力学和生物学环境，骨折痂内会形成不同的组织类型。我们的目的是通过基本的机械生物学模型了解这些组织模式的时间顺序，以了解正常骨愈合过程。实验数据源自先前在绵羊上进行的一项广泛的 3mm 胫骨截骨术动物实验。利用最近的实验数据，硬骨痂的形成被模拟为一种具有增加的刚度和降低的孔隙率的多孔材料。采用了一个基本的唯象模型，其中包含少量的模拟参数，这允许进行全面的参数研究。该模型区分了通过软骨内成骨和膜内成骨形成新骨。为了评估计算机模拟的结果，将模拟的组织图像与绵羊正常愈合过程中从实验中获得的组织图像进行了比较。对组织形成的调节阈值的参数研究进行了研究，并改变了生物刺激的来源（包括干细胞等）。结果发现，在很大的阈值范围内，可以在计算机上再现硬骨痂的形成。然而，仅在（i）对组织分化的阈值进行相当具体的选择，以及（ii）假设骨膜处的生物刺激源很强的情况下，才观察到骨膜侧软骨对骨折间隙的桥接。
