Koria Lekha, Mengoni Marlène, Brockett Claire
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK.
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds, LS2 9JT, UK.
J Mech Behav Biomed Mater. 2020 Oct;110:103931. doi: 10.1016/j.jmbbm.2020.103931. Epub 2020 Jul 14.
Tissue-level properties of bone play an important role when characterising apparent-level bone biomechanical behaviour and yet little is known about its effect at this hierarchical level. In combination with trabecular morphological data these properties can be used to predict bone strength, which becomes an invaluable tool for clinicians in patient treatment planning. This study developed specimen-specific micro-finite element (μFE) models using validated continuum-level models, containing grayscale-derived material properties, to indirectly establish tissue-level properties of porcine talar subchondral bone. Specimen-specific continuum finite element (hFE) models of subchondral trabecular bone were setup using μCT data of ten cylindrical specimens extracted from juvenile porcine tali. The models were validated using quasi-static uniaxial compression testing. Validated hFE models were used to calibrate the tissue modulus of corresponding μFE models by minimising the difference between the μFE and hFE stiffness values. Key trabecular morphological indices (BV/TV, DA, Conn.D, Tb.Th, EF) were evaluated. Good agreement was observed between hFE models and experiment (CCC = 0.66). Calibrated E was 504 ± 37.65 MPa. Average BV/TV and DA for μFE specimens were 0.37 ± 0.05 and 0.68 ± 0.11, respectively. BV/TV (r = 0.667) correlated highly with μFE stiffness. The small intra-specimen variation to tissue-level properties suggests that variations to apparent-level stiffness originate from variations to microarchitecture rather than tissue mechanical properties.
在表征表观水平的骨生物力学行为时，骨的组织水平特性起着重要作用，但目前对其在这一层次水平上的影响知之甚少。结合小梁形态学数据，这些特性可用于预测骨强度，这成为临床医生进行患者治疗规划的宝贵工具。本研究使用经过验证的连续体水平模型开发了特定标本的微观有限元（μFE）模型，该模型包含灰度衍生的材料特性，以间接建立猪距骨软骨下骨的组织水平特性。使用从幼年猪距骨中提取的10个圆柱形标本的μCT数据，建立了软骨下小梁骨的特定标本连续体有限元（hFE）模型。通过准静态单轴压缩试验对模型进行验证。通过最小化μFE和hFE刚度值之间的差异，使用经过验证的hFE模型校准相应μFE模型的组织模量。评估了关键小梁形态学指标（骨体积分数、骨小梁离散度、骨小梁连接密度、骨小梁厚度、弹性模量）。hFE模型与实验结果之间观察到良好的一致性（CCC = 0.66）。校准后的弹性模量为504±37.65MPa。μFE标本的平均骨体积分数和骨小梁离散度分别为0.37±0.05和0.68±0.11。骨体积分数（r = 0.667）与μFE刚度高度相关。标本内组织水平特性的微小变化表明，表观水平刚度的变化源于微观结构的变化，而非组织力学性能的变化。
