Cross A R, Aron D N, Budsberg S C, Foutz T L, Pearman B T, Evans M D
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville 32610-0126, USA.
Am J Vet Res. 1999 May;60(5):615-20.
To determine the validity of finite element analysis (FEA) as a means of examining biomechanical properties of the Kirschner-Ehmer external skeletal fixation system.
10 paired tibiae harvested from skeletally mature dogs weighing between 30 and 38 kg immediately following euthanasia for reasons unrelated to musculoskeletal disease.
A gap fracture was created in each bone; fragments were stabilized with 3 frame configurations (type I, type II, and type III), using enhanced-profile threaded pins. Each bone-frame construct was tested, using a materials testing machine in 3 modes of testing: axial compression (AC), mediolateral (ML) bending, and craniocaudal (CC) bending, for a total of 9 tests/bone. The elastic limit of the constructs was not exceeded during testing. Mean stiffness values were determined from load-displacement curves. A finite element model of each construct was created, using three-dimensional elastic beam elements, and stiffness values were calculated, using FEA. Correlations between experimental and FEA data then were determined.
Significant differences in stiffness were seen among all 3 constructs in CC bending and AC, with stiffness increasing with construct complexity. No significant difference in ML bending stiffness was seen between type-II and type-III constructs; however, both were significantly stiffer than the type-I constructs. The experimental and FEA stiffness data were strongly correlated (AC, r = 0.994; ML bending, r = 0.998; CC bending, r = 0.985).
Strong correlations among experimental and FEA data indicate that FEA is a valid method of comparing stiffness of Kirschner-Ehmer external skeletal fixation constructs.
确定有限元分析（FEA）作为一种检查克氏针-埃默尔外骨骼固定系统生物力学特性方法的有效性。
从30至38千克的骨骼成熟犬中获取10对胫骨，这些犬因与肌肉骨骼疾病无关的原因在安乐死后立即取材。
在每根骨上制造一个间隙骨折；使用增强型螺纹针，通过3种框架构型（I型、II型和III型）对骨折碎片进行固定。使用材料试验机，对每个骨-框架结构进行3种测试模式的测试：轴向压缩（AC）、内外侧（ML）弯曲和头尾向（CC）弯曲，每根骨总共进行9次测试。测试过程中未超过结构的弹性极限。从载荷-位移曲线确定平均刚度值。使用三维弹性梁单元创建每个结构的有限元模型，并通过有限元分析计算刚度值。然后确定实验数据与有限元分析数据之间的相关性。
在CC弯曲和AC测试中，所有3种结构的刚度均存在显著差异，刚度随结构复杂性增加而增大。II型和III型结构之间在ML弯曲刚度方面无显著差异；然而，二者均比I型结构显著更硬。实验刚度数据与有限元分析刚度数据高度相关（AC，r = 0.994；ML弯曲，r = 0.998；CC弯曲，r = 0.985）。
实验数据与有限元分析数据之间的强相关性表明，有限元分析是比较克氏针-埃默尔外骨骼固定结构刚度的有效方法。
