Orthopaedic Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China; Suzhou Origin Medical Technology Co. Ltd., Suzhou 215513, China.
Biomaterials. 2015 Sep;64:57-69. doi: 10.1016/j.biomaterials.2015.06.031. Epub 2015 Jun 20.
High-purity magnesium (HP Mg) takes advantage in no alloying toxic elements and slower degradation rate in lack of second phases and micro-galvanic corrosion. In this study, as rolled HP Mg was fabricated into screws and went through in vitro immersion tests, cytotoxicity test and bioactive analysis. The HP Mg screws performed uniform corrosion behavior in vitro, and its extraction promoted cell viability, bone alkaline phosphatase (ALP) activity, and mRNA expression of osteogenic differentiation related gene, i.e. ALP, osteopontin (OPN) and RUNX2 of human bone marrow mesenchymal stem cells (hBMSCs). Then HP Mg screws were implanted in vivo as load-bearing implant to fix bone fracture and subsequently gross observation, range of motion (ROM), X-ray scanning, qualitative micro-computed tomography (μCT) analysis, histological analysis, bending-force test and SEM morphology of retrieved screws were performed respectively at 4, 8, 16 and 24 weeks. As a result, the retrieved HP Mg screws in fixation of rabbit femoral intracondylar fracture showed uniform degradation morphology and enough bending force. However, part of PLLA screws was broken in bolt, although its screw thread was still intact. Good osseointegration was revealed surrounding HP Mg screws and increased bone volume and bone mineral density were detected at fracture gap, indicating the rigid fixation and enhanced fracture healing process provided by HP Mg screws. Consequently, the HP Mg showed great potential as internal fixation devices in intra-articular fracture operation.
高纯度镁（HP Mg）具有无合金有毒元素和缺乏第二相和微电偶腐蚀的较慢降解速率的优势。在这项研究中，将轧制的 HP Mg 制成螺钉并进行体外浸泡试验、细胞毒性试验和生物活性分析。HP Mg 螺钉在体外表现出均匀腐蚀行为，其浸提液促进了细胞活力、碱性磷酸酶（ALP）活性以及成骨分化相关基因（即人骨髓间充质干细胞（hBMSCs）中的 ALP、骨桥蛋白（OPN）和 RUNX2）的 mRNA 表达。然后，将 HP Mg 螺钉作为承重植入物植入体内以固定骨折，随后分别在 4、8、16 和 24 周时进行大体观察、运动范围（ROM）、X 射线扫描、定性微计算机断层扫描（μCT）分析、组织学分析、弯曲力测试和取回的螺钉的 SEM 形态。结果表明，在固定兔股骨髁内骨折时，取回的 HP Mg 螺钉表现出均匀的降解形态和足够的弯曲力。然而，部分 PLLA 螺钉在螺栓中断裂，尽管其螺钉螺纹仍然完整。在 HP Mg 螺钉周围显示出良好的骨整合，并且在骨折间隙处检测到增加的骨体积和骨矿物质密度，这表明 HP Mg 螺钉提供了刚性固定和增强的骨折愈合过程。因此，HP Mg 作为关节内骨折手术中的内固定装置具有很大的潜力。
