Development of diagnostic device for fracture healing by a modal analysis

骨的硬度随骨折愈合过程而变化。本研究旨在开发一种基于骨模态分析方法的骨折愈合诊断装置。（材料与方法）以成年家兔胫骨为实验对象。远端固定在装置上。横波从1Hz扫到200Hz，持续0.5秒，用来振荡骨头。加速度传感器安装在胫骨近端，检测平移振荡输出加速器。利用FFT分析仪对输出波形进行分析。骨中部用5%甲酸脱钙。作者将该骨作为胫骨骨折愈合模型。骨折愈合程度由浸泡时间决定。即脱钙时间分别为0、6、18、24、48小时。此外，通过图像分析来测量Softex图像的密度来检查脱钙水平。（结果）未脱钙处理骨的共振频率为120Hz。共振频率随骨脱钙程度而降低。骨在甲酸中浸泡6、18、24和48小时，分别在114、103、85和20Hz处观察各共振频率。另一方面，通过Softex图像的密度来评估脱钙的程度。在脱钙6、18、24、48 h时，分别为25.6%、28.9%、30.4%、41.8%。

Stiffness of bone is changed depending on the fracture healing process. This study was conducted to develop a diagnostic device for fracture healing of bone by a modal analysis method of bone. (Materials and Method) The tibial bone of adult rabbit was subjected. The distal end was fixed on the device. A transverse wave, which was swept from 1Hz to 200Hz for 0.5sec was made to oscillate the bone. The acceleration sensor was installed in the proximal end of the tibia, and detected the translated oscillation output accelerator. The output wave form was analyzed by a FFT analyzer. The middle part of the bone was decalcificated with 5% formic acid. The authors regarded the bone as a fracture healing model of tibial bone. The fracture healing level was determined by the soaking time period. Namely, the decalcification time period was 0, 6, 18, 24, and 48hrs, respectively. Moreover, the level of decalcification was checked by an image analysis to measure the density of the Softex image. (Result) The resonance frequency of the bone without decalcification treatment was 120Hz. The resonance frequency has decreased along with the level of the decalcification of bone. Each resonance frequency, which the bone was soaked in the formic acid for 6, 18, 24, and 48hrs, was observed at 114, 103, 85, and 20Hz, respectively. On the other hand, the level of the decalcification was evaluated by the density of the Softex image. Each level was 25.6%, 28.9%, 30.4%, and 41.8% at the decalcification period of 6, 18, 24, and 48 hrs, respectively.