生物可降解Zn-ZnMg-Mg梯度合金髓内钉研制及其固定股骨干骨折愈合机理的生物力学研究
发布时间：2019-06-20 05:26
【摘要】：随着社会经济的发展、交通工具的普及和建筑业快速发展,导致车祸、高空坠落等引起的骨折频发;骨质疏松患者和过于肥胖患者的增多以及人口老龄化进程的加快,需要骨缺损治疗的患者逐年递增,对骨修复材料及功能重建的需求越来越多。内固定物固定治疗骨折是目前临床主要的常规方案和技术手段。本文设计了一种生物可降解Zn-ZnMg-Mg梯度合金材料骨科内固定物,使其能满足骨折早期愈合坚强固定要求,随后在体内逐渐降解过渡到动态固定,避免固定骨折部位应力遮挡效应达到骨折愈合目的。最终内固定物在体内失去材料力学性能被完全吸收,避免二次手术取出。本文进行了生物可降解Zn-ZnMg-Mg梯度合金髓内钉研制及其固定股骨干骨折愈合机理的生物力学相关研究。根据骨折愈合生物力学机理对于材料的需求及镁、锌金属材料降解腐蚀特性,设计研制出一种生物可降解Zn-ZnMg-Mg梯度合金。该合金以镁金属为基体,通过粉末扩散退火渗锌的方法在镁基体表面形成锌镁复合层,再用电镀法镀一锌层。提出了一种制备镁基表面镀锌的工艺,并通过表面形貌观察、物相分析、体外浸泡实验和电化学测试,对其进行了层厚测量、成分检测、腐蚀速率评价,结果表明该生物可降解梯度合金材料符合预期设计要求。用力学测试及数值模拟评价铁、镁、锌、梯度合金材料及人皮质骨的生物力学性能,实验结果显示各金属的生物力学性质一致性较高,有限元数字模拟得出的弹性模量基本符合髓内钉材料属性,梯度合金材料弹性模量低于纯铁的弹性模量,但高于纯镁、纯锌的弹性模量。得出Zn-ZnMg-Mg梯度合金材料力学性能更优,为生物可降解材料的设计提供了可靠的力学参考依据。建立梯度合金髓内钉与铁制髓内钉置入固定大鼠股骨干骨折的模型,通过大体观察、影像学检查、Micro-CT重建、组织形态学及力学性能测试等指标。检测了骨折愈合过程中不同时期大鼠骨折部位骨痂及可降解梯度合金髓内钉在体内的生物学特性,观察了生理载荷下大鼠骨折愈合过程和治疗骨折的效果,实验结果显示在骨折愈合早期梯度合金组不稳定的生物力学环境不利于骨折愈合,但通过骨痂体积的增大代偿骨折端的不稳,在骨折愈合后期,随着梯度合金髓内钉吸收,骨痂的生物力学性能和矿化水平明显提高。对梯度合金髓内钉和铁制髓内钉固定大鼠股骨干骨折进行数值仿真计算,模拟了不同时期骨折愈合和髓内钉降解对骨折愈合的生物力学影响。得到了大鼠骨折愈合不同时期的髓内钉应力及股骨应力,在大鼠股骨干骨折愈合早期,梯度合金髓内钉应力峰值、股骨应力峰值及应力分布与铁制髓内钉相似,之后梯度合金髓内钉应力逐渐减小,明显低于铁制髓内钉。结果显示符合骨折愈合要求,早期实现坚强固定,之后通过逐渐降解达到动态固定,避免应力遮挡,实现骨折愈合。
[Abstract]:With the development of social economy, the popularization of transportation and the rapid development of construction industry, resulting in frequent fracture caused by car accidents and falling from high altitude, the increase of osteoporosis patients and obese patients and the acceleration of population aging process, the number of patients in need of bone defect treatment is increasing year by year, and there is more and more demand for bone repair materials and functional reconstruction. Internal fixation is the main routine and technical method in the treatment of fracture. In this paper, a biodegradable Zn-ZnMg-Mg gradient alloy material orthopaedic internal fixation was designed to meet the requirements of early fracture healing and rigid fixation, and then gradually degraded and transitioned to dynamic fixation in vivo to avoid the stress occlusion effect of fixed fracture site to reach the goal of fracture healing. Finally, the internal fixation lost the mechanical properties of the material in the body and was completely absorbed to avoid the removal of secondary surgery. In this paper, the development of biodegradable Zn-ZnMg-Mg gradient alloy intramedullary nail and the biomechanical study on the mechanism of fracture healing of fixed thigh shaft were carried out. According to the demand of fracture healing biomechanical mechanism and the degradation and corrosion characteristics of magnesium and zinc metal materials, a biodegradable Zn-ZnMg-Mg gradient alloy was designed and developed. The alloy is based on magnesium metal and forms a zinc-magnesium composite layer on the surface of magnesium matrix by powder diffusion and annealed galvanizing, and then plating a zinc layer by electroplating. A process for preparing zinc plating on magnesium base surface was proposed. The coating thickness, composition detection and corrosion rate of the biodegradable gradient alloy were measured by surface morphology observation, phase analysis, immersion test in vitro and electrochemical test. The results show that the biodegradable gradient alloy material meets the expected design requirements. The biomechanical properties of iron, magnesium, zinc, gradient alloy materials and human cortical bone were evaluated by mechanical test and numerical simulation. The experimental results show that the biomechanical properties of each metal are consistent. The elastic modulus obtained by finite element digital simulation basically accords with the properties of intramedullary nailing material. The elastic modulus of gradient alloy material is lower than that of pure iron, but higher than that of pure magnesium and pure zinc. It is concluded that the mechanical properties of Zn-ZnMg-Mg gradient alloy materials are better, which provides a reliable mechanical reference for the design of biodegradable materials. The model of femoral shaft fracture fixed with gradient alloy intramedullary nail and iron intramedullary nail was established. The indexes such as gross observation, imaging examination, Micro-CT reconstruction, histomorphology and mechanical properties were tested. The biological characteristics of fracture site and biodegradable gradient alloy intramedullary nail in rats at different stages of fracture healing were measured. The process of fracture healing and the effect of fracture treatment under physiological load were observed. The experimental results showed that the unstable biomechanical environment of gradient alloy group was not conducive to fracture healing in the early stage of fracture healing, but the instability of fracture end was compensated by the increase of callus volume, and the instability of fracture end was compensated by the increase of callus volume. With the absorption of gradient alloy intramedullary nails, the biomechanical properties and mineralization level of eschar were significantly improved. The biomechanical effects of fracture healing and degradation of intramedullary nail on fracture healing in rats were simulated by numerical simulation of femoral shaft fracture fixed with gradient alloy intramedullary nail and iron intramedullary nail. The intramedullary nail stress and femoral stress in different stages of fracture healing in rats were obtained. in the early stage of fracture healing in rats, the peak stress, peak stress and stress distribution of gradient alloy intramedullary nail were similar to those of iron intramedullary nail, and then the stress of gradient alloy intramedullary nail decreased gradually, which was significantly lower than that of iron intramedullary nail. The results showed that it met the requirements of fracture healing and achieved strong fixation in the early stage, and then achieved dynamic fixation through gradual degradation to avoid stress occlusion and achieve fracture healing.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R683;R318.08
本文编号：2502973
[Abstract]:With the development of social economy, the popularization of transportation and the rapid development of construction industry, resulting in frequent fracture caused by car accidents and falling from high altitude, the increase of osteoporosis patients and obese patients and the acceleration of population aging process, the number of patients in need of bone defect treatment is increasing year by year, and there is more and more demand for bone repair materials and functional reconstruction. Internal fixation is the main routine and technical method in the treatment of fracture. In this paper, a biodegradable Zn-ZnMg-Mg gradient alloy material orthopaedic internal fixation was designed to meet the requirements of early fracture healing and rigid fixation, and then gradually degraded and transitioned to dynamic fixation in vivo to avoid the stress occlusion effect of fixed fracture site to reach the goal of fracture healing. Finally, the internal fixation lost the mechanical properties of the material in the body and was completely absorbed to avoid the removal of secondary surgery. In this paper, the development of biodegradable Zn-ZnMg-Mg gradient alloy intramedullary nail and the biomechanical study on the mechanism of fracture healing of fixed thigh shaft were carried out. According to the demand of fracture healing biomechanical mechanism and the degradation and corrosion characteristics of magnesium and zinc metal materials, a biodegradable Zn-ZnMg-Mg gradient alloy was designed and developed. The alloy is based on magnesium metal and forms a zinc-magnesium composite layer on the surface of magnesium matrix by powder diffusion and annealed galvanizing, and then plating a zinc layer by electroplating. A process for preparing zinc plating on magnesium base surface was proposed. The coating thickness, composition detection and corrosion rate of the biodegradable gradient alloy were measured by surface morphology observation, phase analysis, immersion test in vitro and electrochemical test. The results show that the biodegradable gradient alloy material meets the expected design requirements. The biomechanical properties of iron, magnesium, zinc, gradient alloy materials and human cortical bone were evaluated by mechanical test and numerical simulation. The experimental results show that the biomechanical properties of each metal are consistent. The elastic modulus obtained by finite element digital simulation basically accords with the properties of intramedullary nailing material. The elastic modulus of gradient alloy material is lower than that of pure iron, but higher than that of pure magnesium and pure zinc. It is concluded that the mechanical properties of Zn-ZnMg-Mg gradient alloy materials are better, which provides a reliable mechanical reference for the design of biodegradable materials. The model of femoral shaft fracture fixed with gradient alloy intramedullary nail and iron intramedullary nail was established. The indexes such as gross observation, imaging examination, Micro-CT reconstruction, histomorphology and mechanical properties were tested. The biological characteristics of fracture site and biodegradable gradient alloy intramedullary nail in rats at different stages of fracture healing were measured. The process of fracture healing and the effect of fracture treatment under physiological load were observed. The experimental results showed that the unstable biomechanical environment of gradient alloy group was not conducive to fracture healing in the early stage of fracture healing, but the instability of fracture end was compensated by the increase of callus volume, and the instability of fracture end was compensated by the increase of callus volume. With the absorption of gradient alloy intramedullary nails, the biomechanical properties and mineralization level of eschar were significantly improved. The biomechanical effects of fracture healing and degradation of intramedullary nail on fracture healing in rats were simulated by numerical simulation of femoral shaft fracture fixed with gradient alloy intramedullary nail and iron intramedullary nail. The intramedullary nail stress and femoral stress in different stages of fracture healing in rats were obtained. in the early stage of fracture healing in rats, the peak stress, peak stress and stress distribution of gradient alloy intramedullary nail were similar to those of iron intramedullary nail, and then the stress of gradient alloy intramedullary nail decreased gradually, which was significantly lower than that of iron intramedullary nail. The results showed that it met the requirements of fracture healing and achieved strong fixation in the early stage, and then achieved dynamic fixation through gradual degradation to avoid stress occlusion and achieve fracture healing.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：R683;R318.08
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1 马剑雄;生物可降解Zn-ZnMg-Mg梯度合金髓内钉研制及其固定股骨干骨折愈合机理的生物力学研究[D];天津大学;2015年
，本文编号：2502973
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