Kuhn Florian, Clausing Rasmus Johannes, Stiller Alexander, Fonseca Ulloa Carlos Alfonso, Foelsch Christian, Rickert Markus, Jahnke Alexander
Laboratory of Biomechanics, Department of Orthopaedics and Orthopaedic Surgery, Justus-Liebig-University Giessen, Klinikstrasse 29, 35392, Giessen, Germany.
Department of Orthopaedics and Orthopaedic Surgery, University Hospital Giessen and Marburg (UKGM), Klinikstraße 33, 35392, Giessen, Germany.
J Orthop. 2022 Jul 11;33:48-54. doi: 10.1016/j.jor.2022.07.003. eCollection 2022 Sep-Oct.
Evaluation of the mechanical behavior of the microstructure of cancellous bone seems important for the understanding of the mechanical behavior of bone. Prevention and treatment of fragility fractures due to osteoporosis is a major challenge according to ageing population. A bone model might help to assess fracture risk. Measurement of single trabeculae of bone should give further information compared with bone densitometry alone. This study measures the mechanical properties of single cancellous trabeculae derived from human proximal humerus.
34 single trabeculae dissected from human humeral heads were measured and evaluated mechanically. Trabeculae were fixed on microscope slides and geometrical data were reported during axial rotation of the specimens to measure the transverse section using computer aided design (CAD). The samples were subjected to a two-point bending test and were loaded with a measure-stamp at a defined distance. Force and deflection were measured by high-resolution sensors. The E-modulus was then calculated in combination with finite elements method simulation (FEM), using the previously obtained CAD-Data.
The average E-modulus from 34 valid measurements of human humeral trabeculae was 1678 MPa with a range from 829 to 3396 MPa, which is consistent with existing literature. The planned additional validation of the measurement method using manufactured three-dimensional synthetic trabeculae with known mechanical properties showed an average elastic modulus of single trabeculae of 51.5 MPa, being two dimensions lower than the value reported in the datasheet of the plastic.
This newly developed, time and cost-efficient procedure allows the measurement of E-modulus in single trabeculae. Measurement of mechanic parameters of single trabeculae might give insights on mechanic behavior of bone and be relevant for the research of systemic bone diseases, complementing the existing data on bone-mineral-density. Further examination of single trabeculae of human cancellous bone should give an insight on the mechanical behavior of bone also considering systemic bone diseases.
评估松质骨微观结构的力学行为对于理解骨骼的力学行为似乎很重要。随着人口老龄化，预防和治疗因骨质疏松症导致的脆性骨折是一项重大挑战。骨模型可能有助于评估骨折风险。与单独的骨密度测量相比，对单个骨小梁的测量应该能提供更多信息。本研究测量了源自人类近端肱骨的单个松质骨小梁的力学性能。
对从人类肱骨头解剖出的34个单个骨小梁进行力学测量和评估。将骨小梁固定在载玻片上，并在标本轴向旋转期间报告几何数据，以便使用计算机辅助设计（CAD）测量横截面积。对样品进行两点弯曲试验，并在规定距离处用测量压头加载。通过高分辨率传感器测量力和挠度。然后结合有限元方法模拟（FEM），使用先前获得的CAD数据计算弹性模量。
对人类肱骨骨小梁进行的34次有效测量的平均弹性模量为1678MPa，范围为829至3396MPa，这与现有文献一致。使用具有已知力学性能的制造的三维合成骨小梁对测量方法进行的计划中的额外验证显示，单个骨小梁的平均弹性模量为51.5MPa，比塑料数据表中报告的值低两个数量级。
这种新开发的、省时且经济高效的程序允许测量单个骨小梁中的弹性模量。单个骨小梁力学参数的测量可能有助于深入了解骨骼的力学行为，并且与系统性骨疾病的研究相关，补充了现有的骨矿物质密度数据。对人类松质骨单个骨小梁的进一步检查应该能深入了解骨骼的力学行为，同时也考虑系统性骨疾病。
