【作者】 李杰；

【导师】 蒋电明；

【作者基本信息】 重庆医科大学 ， 外科学， 2005， 硕士

【摘要】 各种原因导致的骨端缺损临床上较为常见,由于其解剖位置特殊且多为不规则缺损,其修复问题一直困扰着矫形外科医生。羟基磷灰石(hydroxyapatite,HA)具有良好的生物相容性和骨传导能力,在临床上用于骨缺损的修复,迄今已有几十年的历史。但由于普通羟基磷灰石脆性大,其碎裂的颗粒易于从修复部位移位、且其具有韧性差、不易塑形等缺点,只能用于非负重部位的骨缺损充填修复,而对承重较大部位的缺损,如长骨骨端缺损则不能令人满意。国内学者李玉宝等研制出类骨纳米羟基磷灰石/聚酰胺66(nano-hydroxyapatite/polyamide-66, n-HA/PA66),是具有我国自主知识产权和国际领先水平的新型纳米晶骨修复替代材料,它是将纳米羟基磷灰石(n-HA)的优良生物相容性、刚性、尺寸稳定性和高分子聚己二酰己二胺(PA66)的韧性完整地结合起来,其在形态、结构和组成上与人体骨中磷灰石纳米针晶相似;而力学性能,特别是抗压、抗弯强度和弹性模量与人体皮质骨相近。纳米羟基磷灰石/聚酰胺(n-HA/PA66)复合材料中,n-HA 的形态、大小、结晶度和晶体结构都与人骨磷灰石晶体相似。PA66 是已作为外科缝线长期应用于临床的高分子聚合物。它们通过化学键合形成具有良好生物活性和力学性能的仿生生物材料[1]。研究表明可注射性 n-HA/PA66 复合骨水泥具有良好的重庆医科大学硕士研究生学位论文-3-可注射性和抗血流腐蚀性,它能够在空气中、生理盐水或血液中原位固化,固化时间为 7～20 分钟,它的优点是固化后其内部可形成许多微孔,压缩强度可达 53Mpa。其固相为 n-HA/PA66 粉末,液相为乙醇和少量金属盐的混合液,将两者按一定比例混合后,很容易调制成糊状或面团状的材料来进行任意塑形。据此,我们建立了兔胫骨干骺端骨缺损模型,对纳米羟基磷灰石/聚酰胺 66(n-HA/PA66)液态可注射的骨水泥的成骨能力和用于修复骨端缺损的可行性进行实验研究。目的:通过将纳米羟基磷灰石/聚酰胺(n-HA/PA66)复合材料骨水泥用于兔胫骨骨端缺损的动物实验,并以在临床上广泛应用的丙烯酸甲酯骨水泥( polymethylmethacrylate , PMMA),和磷酸钙骨水泥(calcium phosphate cement, CPC)作为动物实验对照,研究n-HA/PA66 骨水泥修复骨端缺损的能力及其对骨愈合的影响,以及n-HA/PA66 复合骨水泥修复兔胫骨骨端缺损后的生物力学变化。试图从组织学、影像学及生物力学的角度,通过检测修复速度、质量、骨传导特性等的相关指标,对 n-HA/PA66 骨水泥用于修复骨端缺损的可行性和成骨能力进行综合评价,并为其进一步的研究开发及临床应用研究提供参考资料及理论依据。方法:选择同种系新西兰大白兔,5 月龄以上,生理状态正常,雌雄不限,体重 2.5～3.1 ㎏健康成年兔 48 只(由重庆医科大学动物实验中心提供)。将 48 只兔随机分成三组,编号 A、B、C 每组 16 只(32侧胫骨髁),每只兔子行双侧胫骨髁钻孔直径 3mm,深 5mm。A 组双侧分别注入 n-HA/PA66 复合材料骨水泥和 PMMA,B 组双侧分别注入更多还原

【Abstract】 All sorts of extremities defects caused by trauma, infection orresection of a tumour is a difficult problem puzzled plastic surgeons. Itis well known that hydroxyapatite (HA) is a biocompatible material withgood osteoconductivable properties. It has been known that HA canpromote early bone ingrowth. However, this bone substitute ismechanically weak and its particles might migrate from the site of theimplant,on the other hand,the general hydroxyapatite are too brittle to trim .these shortcomings were restricted in clinical for unload-bearing bonerepair The nano-hydroya-patite and polyamide66 (n-HA/PA66) is a newtype of inorganic-organic biomimetic component. Results of the test andanalytical studies indicated that the distribution of n-HA homogeneously inpolyamide matrix, nanograde needle-shape apatite crystals of n-HA wassimilar to bone apatite. A new injectable n-HA/PA66 composite wasinvestigated. The composite has good injectable properties, and can beeasily handled as paste, injecting with a syringe and hardening in situ.. Theinjectable n-HA/PA66 composite cement has a reasonable setting time,high mechanical strength, excellent washout and blood decay resistantproperties.In this experiment,We will study the osteoconductivity ofn-HA/PA66 and the feasibility to repair condyles tibia defect of rabbit withthe n-HA/PA66 composite cement. 【OBJECTIVE】The purpose of this study was to evaluate thebiocompatibility and osteoconductivity of a new bone cement, the cementwas composed mainly of nano-hydroyapatite (n-HA) and polyamide66(PA66);study the ability of repairing condyles tibia defect of rabbit with theinjectable bioactive bone cement ;and study the feasibility use it as theinjectable bone substitute , to provided referenced data for the advanceclinical study. 【METHODS】The animal models of condyles of tibia defect createdwith surgery in the New Zealand white rabbits ,and were injectedn-HA/PA66 cement as the experimental group, injected PMMA and CPC asthe experimental control group. The effect were observed by gross andX-ray and histopathlogical examnation , histological studies wereperformed on thin un-decalcified, In the mean time , the Magneticresonance imagine(MRI) and Biomechanics of new bone were determinedat 2,4,6,8,12W after operation. 【RESULTS】Results of this study showed osteoblastic activity andnew bone formation at the interface between the condyles of tibia defectbone and the cement in the experimental group and CPC group.Nounfavorable reaction was noted in the n-HA/PA66-applied sites .Thebiocompatibility and osteoconductivable properties of n-HA/PA66 cementwere superior to CPC and PMMA, No statistically significant difference wasnoted in the experimental or control sites under the data of biomechanics(P>0.05. 【 CONCLUSIONS 】 Our results show,the nano-hydroxyapatite/Polyamide Composite cement have good biocompatibility and has goodosteoconductivity, and the injectable n-HA/PA66 cement had used torepair condyles of rabbit tibia defect successfully,showed promisingprospect for extremities defect repairing.更多还原