Department of Orthopaedic Surgery, Tohoku University Graduate School of Medicine.
Department of Diagnostic Radiology, Tohoku University Graduate School of Medicine.
Tohoku J Exp Med. 2021 Oct;255(2):135-142. doi: 10.1620/tjem.255.135.
The optimal Young's modulus of material of orthopedic devices for fracture treatment is still unknown. The purpose of present study was to evaluate the impacts of intramedullary nails composed of a titanium alloy with low Young's modulus, on accelerating fracture healing compared with stainless steel with high Young's modulus. A β-type TiNbSn alloy with a low Young's modulus close to that of human cortical bone was developed for clinical application. TiNbSn alloy with a Young's modulus of 45 GPa and stainless steel with a Young's modulus of 205 GPa were compared, with respect to the impacts on fracture healing. Fracture and fixation using intramedullary nail were performed on the right tibiae of C57BL/6 mice. The assessment of bone healing was performed via micro-computed tomography, histomorphometry, and quantitative reverse transcription polymerase chain reaction. In micro-computed tomography, larger bone volumes were observed in the fracture callus treated with TiNbSn alloy in comparison with those treated with stainless steel. Histological assessments confirmed accelerated cartilage absorption and new bone formation in the TiNbSn alloy group compared with the stainless steel group. The expression of Col1a1, Runx2, Dkk1, and Acp5 was higher in the TiNbSn alloy group, while that of Col2a1 and Col10a1 was lower in the late phase. The present study demonstrated that the fixation by intramedullary nails with TiNbSn alloy offered an accelerated fracture healing with promotion of bone formation via increased Runx2 expression. TiNbSn alloy might be a promising material for fracture treatment devices.
用于骨折治疗的矫形装置的最佳杨氏模量材料仍不清楚。本研究的目的是评估与具有高杨氏模量的不锈钢相比，由杨氏模量低的钛合金制成的髓内钉对加速骨折愈合的影响。开发了一种具有接近人皮质骨杨氏模量的低杨氏模量的β型 TiNbSn 合金用于临床应用。比较了杨氏模量为 45GPa 的 TiNbSn 合金和杨氏模量为 205GPa 的不锈钢对骨折愈合的影响。在 C57BL/6 小鼠的右侧胫骨上进行髓内钉骨折和固定。通过 micro-CT、组织形态计量学和定量逆转录聚合酶链反应评估骨愈合。在 micro-CT 中，与不锈钢处理的骨折痂相比，TiNbSn 合金处理的骨折痂的骨体积更大。组织学评估证实 TiNbSn 合金组的软骨吸收和新骨形成加速，而不锈钢组则没有。TiNbSn 合金组中 Col1a1、Runx2、Dkk1 和 Acp5 的表达较高，而 Col2a1 和 Col10a1 的表达在后期较低。本研究表明，TiNbSn 合金髓内钉固定可通过增加 Runx2 表达促进骨形成，从而加速骨折愈合。TiNbSn 合金可能是一种有前途的骨折治疗装置材料。
