Abstract The aim of this study was to use degradation prediction and in-vivo evaluation to inspire a novel design of magnesium (Mg) implant having a coral-like open-cell porous interior and an outer solid casing. In this design, the porous interior acts as a bone-mimic channel for tissue infiltration and cell adhesion, while the solid casing enables better structural strength and integrity. Different porosities of porous interiors, combined with different wall thicknesses of outer casing, were designed. By implementing a continuum damage mechanics (CDM)-based biodegradation model into finite element simulations, the mechanical properties and degradation rates of the implant were predicted. The results showed that the implant with 70%–75% porosity and 0.5 mm wall thickness had the optimal structural strength and degradation rate. This implant structure was then fabricated. Compression tests and X-ray computed tomography (CT) scanning were carried out to investigate the material properties and the structural transformation of the implants respectively. Moreover, an in-vivo rabbit model was used to evaluate the degradation behaviours of the implant at different time points. The results showed that this novel Mg implant had a relatively sturdy material strength and the porous structure did benefit the ingrowth of bone tissue and expedite the healing process.

中文翻译：

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用于骨科应用的珊瑚状开孔多孔可降解镁植入物的新设计

摘要 本研究的目的是利用降解预测和体内评估来激发具有珊瑚状开孔多孔内部和外部固体外壳的镁 (Mg) 植入物的新设计。在这种设计中，多孔内部充当组织浸润和细胞粘附的骨模拟通道，而实心外壳可实现更好的结构强度和完整性。设计了不同孔隙率的多孔内部，结合不同的外壳壁厚。通过在有限元模拟中实施基于连续损伤力学 (CDM) 的生物降解模型，预测了植入物的机械性能和降解率。结果表明，具有 70%–75% 孔隙率和 0.5 mm 壁厚的植入物具有最佳的结构强度和降解率。然后制造该植入物结构。进行压缩测试和 X 射线计算机断层扫描 (CT) 扫描以分别研究植入物的材料特性和结构转变。此外，使用体内兔模型来评估植入物在不同时间点的降解行为。结果表明，这种新型镁植入物具有相对坚固的材料强度，多孔结构确实有利于骨组织的向内生长并加速愈合过程。体内兔模型用于评估植入物在不同时间点的降解行为。结果表明，这种新型镁植入物具有相对坚固的材料强度，多孔结构确实有利于骨组织的向内生长并加速愈合过程。体内兔模型用于评估植入物在不同时间点的降解行为。结果表明，这种新型镁植入物具有相对坚固的材料强度，多孔结构确实有利于骨组织的向内生长并加速愈合过程。