Szivek J A, Johnson E M, Magee F P
Department of Surgery, University of Arizona, Tucson 85724.
J Invest Surg. 1992 Apr-Jun;5(2):91-108. doi: 10.3109/08941939209012426.
Subminiature single element and rosette strain gauges used for deformation measurement were prepared for surgical implantation using a technique published previously (Szivek JA, Magee FP. J Invest Surg. 1989;2:195-206). During surgery, gauges were placed on the anterior, lateral, and medial aspects of the mid-diaphysis of one femur in six greyhounds. Motion and gait analyses were performed to ensure uniform weight bearing prior to strain monitoring. In vivo strain measurements were obtained during normal gait at several speeds on a treadmill. After a 3-month holding period, strain gauges that were implanted on the contralateral femur were monitored. All animals were euthanized and both their femora explanted. Following embedding and histological preparation of the explanted femora, strain measurements were plotted on diagrams of the section shapes of the mid-diaphysis of each femur. Strain distribution diagrams indicated that peak strain levels and strain distributions changed during different phases of gait. Increases in gait speed increased the peak strain levels. In addition, the anterior rather than anterior-lateral aspect of the femur exhibited the highest strain during midstance. Measurements taken from rosette gauges indicated that the principal compressive strain direction was oriented slightly off axis to the long axis of the femur. Measurements from gauges placed along the length of the femur indicated an average strain change of 22.3 microstrain +/- 12.2% over a 2-cm length in the mid-diaphysis. These measurements provide a baseline describing the strain state of the greyhound femur and can be used in computer modeling.
采用先前发表的技术（Szivek JA，Magee FP. J Invest Surg. 1989;2:195 - 206）制备用于变形测量的微型单元素和应变片式应变计，以便进行手术植入。手术过程中，在6只灵缇犬的一根股骨骨干中部的前侧、外侧和内侧放置应变计。在进行应变监测之前，进行运动和步态分析以确保负重均匀。在跑步机上以几种速度的正常步态期间获得体内应变测量值。经过3个月的保持期后，监测植入对侧股骨的应变计。所有动物均实施安乐死并取出双侧股骨。在对取出的股骨进行包埋和组织学制备后，将应变测量值绘制在每根股骨骨干中部截面形状的图表上。应变分布图表明，在步态的不同阶段，峰值应变水平和应变分布会发生变化。步态速度的增加会提高峰值应变水平。此外，在站立中期，股骨的前侧而非前外侧表现出最高应变。从应变片式应变计获得的测量结果表明，主压应变方向与股骨长轴略微偏离轴线。沿股骨长度放置的应变计测量结果表明，在骨干中部2厘米长度范围内，平均应变变化为22.3微应变±12.2%。这些测量结果提供了描述灵缇犬股骨应变状态的基线，可用于计算机建模。
