Brodt M D, Swan C C, Brown T D
Department of Orthopaedic Surgery, University of Iowa, Iowa City 52242, USA.
J Orthop Res. 1998 Jan;16(1):43-9. doi: 10.1002/jor.1100160108.
Despite its widespread use as graft material in orthopaedic surgical procedures, morselized cancellous bone has not yet been well characterized from the standpoint of its mechanical properties. To accommodate the noncohesive nature of this loose particulate form of bone, a triaxial compression test apparatus commonly used in engineering soil mechanics was adapted for the testing of fresh-frozen human morselized cancellous bone specimens. Triaxial compression tests were run to 30% axial strain at five different levels of confining pressure ranging from 0.276 to 0.552 MPa. The measured axial stress versus axial strain behavior was bimodal, characterized initially by relatively stiff linear behavior, then by a rapid transition to a much more compliant (but, again, approximately linear) domain until test cessation. The apparent axial moduli of both response regions were found to be nearly linear functions of the transverse confining pressure. As typically prepared surgically, the distribution of particle size was found to have approximately 80% of the bone graft, by weight, encompassed in particles 0.42-3.2 mm in size. Triaxial tests of samples segregated by size showed that particle size had no appreciable effect on apparent material properties. The nominal Young's modulus and Poisson's ratio of morselized cancellous bone were 100 MPa and 0.2, respectively.
尽管碎松质骨在骨科手术中作为移植材料被广泛使用，但其力学性能尚未得到很好的表征。为了适应这种松散颗粒状骨的非粘性特性，一种工程土力学中常用的三轴压缩试验装置被改装用于测试新鲜冷冻的人碎松质骨标本。在0.276至0.552MPa的五个不同围压水平下进行三轴压缩试验，直至轴向应变达到30%。测得的轴向应力与轴向应变行为呈双峰型，最初表现为相对刚硬的线性行为，然后迅速转变为更柔顺（但同样近似线性）的区域，直至试验结束。发现两个响应区域的表观轴向模量几乎都是横向围压的线性函数。如手术中通常制备的那样，发现按重量计约80%的骨移植材料颗粒尺寸分布在0.42 - 3.2mm的颗粒中。按尺寸分离的样品的三轴试验表明，颗粒尺寸对表观材料性能没有明显影响。碎松质骨的名义杨氏模量和泊松比分别为100MPa和0.2。
