张应力对深筋膜力学特性影响的实验研究

目的：探讨肢体延长过程中张应力对深筋膜力学特性的影响。方法：建立新西兰大白兔双侧胫骨胶体延长动物模型，术后第７ｄ开始延长，延长速度为１ｍｍ／ｄ和２ｍｍ／ｄ，每１２ｈ一个增量，延长率为腔骨长度的１０％和２０％。将正常小腿深筋膜和不同延长速度及延长率作用下的深筋膜制成３０ｍｍ×１０ｍｍ的筋膜条，在室温（１３．２℃）和５ｍｍ／ｍｉｎ的拉伸速度下，以Ｉｎｓｔｒｏｎ１１２２型万能拉伸仪进行单轴拉伸实验，在５次加载－卸载的预调后，拉伸深筋膜直至破裂，记录其载荷－位移曲线，比较正常和肢体延长后各实验组的载荷－位移曲线。结果：正常深筋膜载荷－位移曲线显示典型的胶原组织的载荷－位移规律，肢体延长后的筋膜基本上保持了这一特点，其中以速度延长１ｍｍ／ｄ，延长率２０％的筋膜的载荷－位移曲线与正常筋膜的曲线最为接近。正常的深筋膜极限应变为１４．１１％，极限载荷为２．６９Ｎ，肢体延长后深筋膜的极限载荷有所增加（Ｐ＜０．００１）。结论：肢体延长过程中不同的延长速度、延长率对深筋膜载荷－位移曲线有着显著的影响，延长速度１ｍｍ／ｄ，延长率２０％的载荷－位移曲线最接近正常。

EXPERIMENTAL INVESTIGATION OF THE BIOMECHANICAL PROPERTIES OF DEEP FASCIA IN RESPONSE TO THE TENSION-STRESS PRINCIPLE DURING LIMB LENGTHENING

Objective:To investigate the biomechanical properties of deep fascia of leg in response to the Tension-Stress Principle during limb lengthening. Methods:Limb lengthening animal model was established in New Zealand white rabbits using a unilateral external fixator applied with four pins to the medial surface of the tibia and monofocal proximal diaphyseal osteotomy with closed multiple drill holes and osteoclasis between the second and the third pins.Seven days after operation,distraction was initiated at a rate of 1mm/day and 2mm/day in two steps, and proceeded until increases of 10% and 20% in the initial length of tibia had been achieved.The deep fascia samples of 30x10mm were clamped to the Instron 1122 tensile testdevice at room temperature with the constant tensile rate of 5mm/min.After 5 load-download tensile tests,the samples were elongated until rupture.And the load-displacement curves were automatically generated by the apparatus. Results:The normal deep fascia showed typical load-displacement rules of collagenous tissues.And each experimental fascia kept the characteristics.The curves of fascias at the distraction rate of 1mm/day were closer to the curves of normal fascias.For the normal fascias,the ultimate tension strength was avarage 2.69N,and the strain at rupture was avarage 14.11%.And the ultimate tension strength of the fascias after lengthening increased. Conclusion:These results prove that the Tension-Stress during limb lengthening. has great effect upon foe biomechanical properties of deep fascia.The curves of fascias at a rate of 1mm/day and increase of 20% were the closest to the curves of normal deep fascias.