微弧氧化表面改性3D打印多孔钛合金支撑棒治疗羊距骨骨坏死的研究

目的 探讨微弧氧化（MAO）表面改性3D打印多孔钛合金支撑棒对羊距骨坏死的治疗作用，为其进一步临床应用提供基础。方法 观察3D打印多孔钛合金支撑棒通过MAO表面改性后，其表面形态、元素变化及晶像情况。通过体外细胞实验，研究大鼠成骨细胞在材料表面的黏附、增殖及分化情况。建立羊距骨坏死模型基础，并置入3D打印多孔钛合金支撑棒，探究其在距骨内的稳定性及其成骨修复情况。结果 通过MAO改性，材料表面形成大小均一的多孔微米结构，Ca、P、O元素分布在材料表面，同时表面形成TiO₂晶像。在体外细胞实验中，MAO改性组和对照组均表现出良好的生物相容性，但是MAO改性组在细胞接种后8 h黏附能力优于对照组、接种1、4、7 d后细胞增殖能力均优于对照组，同时接种7 d时细胞分化能力也优于对照组，差异具有统计学意义（P＜0.05）。羊距骨植入实验表明，术后12周两组支撑棒都有骨长入，但是MAO改性组与对照组相比其周围有更多的新生骨长入。定量结果显示MAO组的骨体积分数、骨小梁厚度也优于对照组，差异具有统计学意义（P＜0.05）。结论 仿生的3D打印多孔结构为支撑棒提供了优良的力学性能，MAO表面改性进一步提高了其生物活性，使其在治疗羊距骨早期骨坏死过程中充分发挥了力学和生物学的优势。本临床前研究效果满意，并为其未来临床应用提供了理论和研究基础。

Research on treatment of osteonecrosis of sheep talus by 3D printed porous titanium alloy rod with micro arc oxidation surface modification

Objective To investigate the effect of micro-arc oxidation(MAO) surface modified 3D printed porous titanium alloy rod on the treatment of sheep talus necrosis, so as to provide a basis for its further clinical application.Methods The surface morphology, element changes and crystal state of 3D printed porous titanium alloy support rod were observed after MAO surface modification. The adhesion, proliferation and differentiation of rat osteoblasts on the surface of materials were studied by MTT in vitro. The sheep talus necrosis model was constructed, and the stability and osteogenic repair of 3D printed porous titanium alloy support rod in talus were observed.Results Through MAO modification, porous micron structure with uniform size was formed on the material surface. Ca, P and O elements were distributed on the material surface, and TiO₂ crystal image was formed on the surface at the same time. In vitro cell experiments showed that both MAO modified group and control group presented good biocompatibility. The adhesion ability of MAO modified group was better than that of control group 8 h after cell inoculation, and the cell proliferation ability was better than that of control group 1, 4 and 7 d after inoculation. At the same time, the cell differentiation ability was better than that of control group 7 d after inoculation and the difference was statistically significant (P<0.05). In vivo sheep talus implantation results showed that bone growth of the support rods was found in both groups in 12 weeks after operation, but there were more new bone tissues around the MAO modified group compared with the control group. Quantitative results the bone volume fraction and bone trabecular thickness were also better in MAO modified group than those in the control group, and the differences were statistically significant (P<0.05).Conclusion The bionic 3D printing porous structure provides excellent mechanical properties for support rod. The surface modification by micro arc oxidation further improves its biological activity, which provides its mechanical and biological advantages in the treatment of early bone necrosis of sheep talus. The results of this preclinical study are satisfactory and provides a solid experimental basis for its further application in clinic.