局部注射肝素钠免跟腱系统生物力学性质的变化

摘要

背景: 跟腱腱围炎会导致跟腱生物力学特件的改变,日前以局部注射肝素钠治疗较为普遍,但其对跟腱生物力学特性影响的报道甚少.目的: 观察跟腱劳损后生物力学性质及黏弹性的变化,同时验证肝素钠对跟腱生物力学特性及黏弹性的影响.设计、时间及地点: 于2005-03/12存四川省骨科医院生物力学实验室完成随机对照动物实验.材料: 50只成年日本大耳白兔,体质量(4.10±0.23)kg,用于制备跟腱劳损动物模型.方法: 50只动物随机分为对照组(n=20)、训练组(n=12)和肝素钠组(n=18).动物3周运动训练后继续训练,同时开始跟腱腱围及跟腱止点的肝素局部注射,2次/周.6周后进行跟腱的循环蠕变和应力松弛测定,最后进行跟腱的断裂实验.主要观察指标: 测定不同运动后跟腱的生物力学特性及黏弹性的变化,包括跟腱的横截面积、循环蠕变、滞后环、应力松弛、强度特性和应力-应变.结果: 训练组和肝素钠组动物的滞后环明显减小,应力松弛加快.训练后跟腱的屈服载荷及能量、断裂能量、屈服应力、应变能力明显高于对照组.肝素钠组所有生物力学指标都得到改善.结论: 大强度运动可使跟腱的黏弹性下降,局部注射肝素钠可改善跟腱的强度特性和黏弹性.劳损后跟腱腱围和跟腱止点局部注射肝素钠对改善跟腱系统的强度特性和黏弹性有益.%BACKGROUND: Achilles peritendinitis can change characteristics of mechanical and viscoelastic properties in Achilles tendon, especially the biomechanical properties of Achilles tendon after heparin local injection. OBJECTIVE: To examine the changes of mechanical and viscoelastic properties in Achilles tendon of overuse injuries and the effects of heparin on the mechanical and viscoelastic properties in Achilles tendon. DESIGN, TIME AND SETTIMG: Control animal specimen study was performed at the Biomechanical Laboratory of Sichuan Province Orthopaedic Hospital between March and December 2005. MATERIALS: Fifty Achilles tendon samples from Japanese White rabbits weighing (4.10±0.23) kg were used in this study. METHODS: Rabbits were divided into a control group (n=20), an exercise group (n=12) and a heparin treatment group (n= 18) at random. The rabbits were exercised for 3 weeks, simultaneously the heparin solution were injected into the peritendineum around the insertion of Achilles-calcaneus from the 4th week to the 6th week, twice a week. Then the cyclic stretching on the Achilles tendon was performed for 25 cycles and the tendon was stretched to the constant load to determine the stress relaxation vs, time. Finally the preparation was loaded to failure to measure the biomechanical characteristics of the tendon. MAIN OUTCOME MEARES: The cross-sectional area of the tendon, the cyclic creep lengths versus time, hysteresis loop, the stress relaxation versus time, the strength properties and the stress versus strain characteristics. RESULTS: The normalized area of hysteresis from exercise and heparin groups were significantly reduced in the most cycles, and the stress relaxation reduced more quickly in the exercise and heparin groups. The mean values for yield load and failure energy, yield energy, and yield stress, strain energies from the exercised preparations were higher than those of the controls. All of the mechanical properties from the heparin treated preparations were improved significantly. CONCLUSION: The results showed that the tensile strength and viscoelastic properties of tendon were improved by the management of heparin. It is indicated that the local injections of heparin at the location of peritendineum and tendon-bone insertions are beneficial to viscoelastic and tensile behaviors of the Achilles tendon system.