Small Animal Clinic, University of Veterinary Medicine Hannover, Hannover, Germany.
Biomed Mater. 2013 Aug;8(4):045012. doi: 10.1088/1748-6041/8/4/045012. Epub 2013 Jul 1.
Magnesium alloys are promising implant materials for use in orthopaedic applications. In the present study, screws made of the Mg-alloy ZEK100 (n = 12) were implanted in rabbit tibiae for four and six weeks, respectively. For degradation analysis, in vivo µ-computed tomography (µCT), a determination of the weight changes and SEM/EDX examinations of the screws were performed. Screw retention forces were verified by uniaxial pull-out tests. Additionally, soft-tissue biocompatibility was estimated using routine histological methods (H&E staining) and the immunohistological characterization of B- and T-cells. After six weeks, a 7.5% weight reduction occurred and, in dependence of the implant surrounding, the volume loss (µCT) reached 9.6% (screw head) and 5.0% for the part of the thread in the marrow cavity. Pull-out forces significantly decreased to 44.4% in comparison with the origin value directly after implantation. Soft tissue reactions were characterized by macrophage and lymphocyte infiltration, whereas T-cells as well as B-cells could be observed. In comparison to MgCa0.8-screws, the degradation rate and inflammatory tissue response were increased and the screw holding power was decreased after six weeks. In conclusion, ZEK100-screws seem to be inferior to MgCa0.8-screws, although their initial strength was more appropriate.
镁合金是一种有前途的植入物材料，可用于骨科应用。在本研究中，分别将 ZEK100 镁合金制成的螺钉植入兔胫骨中 4 周和 6 周。为了进行降解分析，进行了体内微计算机断层扫描（µCT）、螺钉重量变化的测定以及 SEM/EDX 检查。通过单轴拔出试验验证了螺钉的保留力。此外，还使用常规组织学方法（H&E 染色）和 B 细胞和 T 细胞的免疫组织化学特征来评估软组织相容性。6 周后，螺钉重量减轻了 7.5%，并且根据植入物周围环境的不同，骨腔中螺纹部分的体积损失（µCT）达到 9.6%（螺钉头部）和 5.0%。与植入后直接获得的原始值相比，拔出力显著降低至 44.4%。组织反应的特征是巨噬细胞和淋巴细胞浸润，同时也观察到 T 细胞和 B 细胞。与 MgCa0.8 螺钉相比，6 周后降解速率和炎症组织反应增加，螺钉固定力降低。总之，尽管 ZEK100 螺钉的初始强度更合适，但它们的性能似乎不如 MgCa0.8 螺钉。
