Development of diagnostic device for fracture healing by a modal analysis

骨的硬度根据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的骨折愈合诊断仪。（材料与方法）成年家兔胫骨标本。远端固定在器械上。用1 ~ 200 Hz的横波对骨进行0.5秒的振荡。加速度传感器安装在胫骨近端，检测平移振荡输出加速度。用FFT分析仪对输出波形进行了分析。骨的中间部分用5%甲酸脱钙。作者将该骨作为胫骨骨折愈合模型。骨折愈合水平由浸泡时间决定。即，脱钙时间段分别为0、6、18、24和48小时。此外，通过图像分析检查脱钙水平以测量Softex图像的密度。（结果）未经脱钙处理的骨共振频率为120 Hz。共振频率随着骨脱钙程度的增加而沿着降低。在甲酸溶液中浸泡6、18、24和48小时后，分别在114、103、85和20 Hz处观察到共振频率。另一方面，通过Softex图像的密度评价脱钙水平。在6、18、24和48小时的脱钙期，各水平分别为25.6%、28.9%、30.4%和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.