Huiskes R, Chao E Y
J Orthop Res. 1986;4(1):68-75. doi: 10.1002/jor.1100040108.
Using results from FEM analyses and experiments as references, analytical methods are applied to develop simple approximate formulas to relate frame rigidity, maximal pin stresses, and peak pin-bone stresses in external fracture fixation (EFF) configurations in axial loading to the most important frame, pin, and bone parameters. It is found that, in a realistic range, the parameters can be adapted to vary the frame rigidity from about 13 N/mm to 17,000 N/mm, thereby reducing the maximal stresses in the pins and at the pin-bone interface by a factor of 140. In particular, when compromises have to be established in the frame characteristics in order to ensure a flexible configuration and limit the stress values at the same time, the formulas presented can provide useful guidelines. The side-bar separation and the pin modulus, in particular, can be adapted to decrease the rigidity, while only moderately increasing the stresses, thereby reducing changes for pin failure, pin-bone loosening, and pin-tract infection. A nomogram is presented for a quick reference to estimated relations between frame characteristics, rigidity, and stresses. It is believed that this material may be of use in EFF design and applications in clinical and animal experimental trials.
以有限元分析和实验结果为参考，应用分析方法来推导简单的近似公式，以关联轴向加载下外固定架骨折固定（EFF）构型中的框架刚度、最大销钉应力和销钉-骨峰值应力与最重要的框架、销钉和骨参数。研究发现，在实际范围内，可调整这些参数使框架刚度从约13N/mm变化到17000N/mm，从而将销钉以及销钉-骨界面处的最大应力降低140倍。特别是，当必须在框架特性方面做出妥协以确保构型灵活并同时限制应力值时，所给出的公式可提供有用的指导。尤其是，可调整侧杆间距和销钉模量以降低刚度，同时仅适度增加应力，从而减少销钉失效、销钉-骨松动和针道感染的发生几率。给出了一张列线图，以便快速查阅框架特性、刚度和应力之间的估算关系。相信该材料可用于临床和动物实验中的EFF设计及应用。
