Low intensity ultrasound stimulation has been used as a strategy to promote fracture healing. This study investigated the mechanism of ultrasound stimulation in enhancing fracture healing. Forty-five adult New Zealand White rabbits were divided into control, microwave treated, and ultrasound stimulation groups. After anesthesia, transverse osteotomy was created at midportion of the fibula bone. Intravital staining followed by fluorescence microscopic examination of new bone formation in the osteotomy site and biomechanical tests on torsional stiffness of the osteotomy site were performed. The difference between each examination was evaluated and analyzed. After ultrasound stimulation, new bone formation in the osteotomy site of the stimulated limb was 23.1-35.8% faster than that of the sham treated limb; the torsional stiffness of the stimulated limb was 44.4-80.0% higher than that of the sham treated limb. In the group of microwave hyperthermia treatment, the new bone formation was higher than that of the sham treated limb, but the difference was not statistically significant. The difference in torsional stiffness between the microwave hyperthermia treated limbs and the sham treated limb was not quite statistically significant. We demonstrated that low intensity ultrasound stimulation could increase the new bone formation and torsional stiffness. These effects probably are not mediated via hyperthermia.

中文翻译：

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超声刺激对骨折愈合的热效应研究。

低强度超声刺激已被用作促进骨折愈合的策略。本研究探讨了超声刺激促进骨折愈合的机制。将四十五只成年新西兰白兔分为对照组，微波处理组和超声刺激组。麻醉后，在腓骨骨的中部进行横向截骨术。进行玻璃体染色，然后在荧光显微镜下检查截骨部位新骨的形成，并对截骨部位的扭转刚度进行生物力学测试。评估并分析每次检查之间的差异。超声刺激后，受刺激肢体截骨部位新骨形成的速度比假手术肢体快了23.1-35.8％；受刺激的肢体的扭转刚度比假手术的肢体高44.4-80.0％。在微波热疗组中，新骨形成高于假手术肢体，但差异无统计学意义。微波热疗治疗的假肢与假手术治疗的假肢之间的扭转刚度差异在统计学上并不十分显着。我们证明了低强度超声刺激可以增加新的骨形成和扭转刚度。这些作用可能不是通过热疗来介导的。微波热疗治疗的假肢与假手术治疗的假肢之间的扭转刚度差异在统计学上并不十分显着。我们证明了低强度超声刺激可以增加新的骨形成和扭转刚度。这些作用可能不是通过热疗来介导的。微波热疗治疗的假肢与假手术治疗的假肢之间的扭转刚度差异在统计学上并不十分显着。我们证明了低强度超声刺激可以增加新的骨形成和扭转刚度。这些作用可能不是通过热疗来介导的。