弹性镍钛合金内固定材料表面修饰及其持续动力压应力对骨折愈合的影响

Effect of elastic nickel-titanium alloy fixator and its continuous compressive stress on healing of fracture

目的:观察弹性镍钛合金内固定材料表面修饰与非修饰产品对骨折愈合的影响,并设立髓内针内固定组进行不同类型内固定后持续动力压应力影响骨折愈合效果的比较。方法:实验于2004-09/2005-03在兰州大学第二医院骨科研究所组织工程实验室完成。选择清洁级4～6月龄的青紫兰兔30只,按随机数字表法分为3组,类金刚石镀膜镍钛合金环抱器组、非镀膜镍钛合金环抱器组、髓内针内固定组,每组10只。每只兔用10g/L戊巴比妥钠(25mg/kg)麻醉后行股外侧切口,制成股骨中段横断骨折模型(为保证动物术后存活质量,只做单侧模型),分别用上述材料固定。4周后取骨折局部骨痂,检测单位骨痂中无机物的质量分数及碱性磷酸酶、骨钙素及肿瘤坏死因子的表达(A)。并取局部肌肉组织、肝组织及脑组织测定镍离子含量。评估镀膜镍钛合金与非镀膜材料组织相容性的差别,以及不同固定物产生的持续压应力对骨折愈合过程中骨痂形成的影响。结果:纳入动物30只,均进入结果分析。①骨痂内无机物的测定及碱性磷酸酶、骨钙素及肿瘤坏死因子的定性及半定量分析:类金刚石镀膜镍钛合金环抱器组、非镀膜镍钛合金环抱器组骨痂中无机物的质量分数、碱性磷酸酶、骨钙素及肿瘤坏死因子的表达(A)均高于髓内针内固定组(分别为0.2857±0.0072,0.2517±0.0099,0.1786±0.0314;228.8324±1.5952,225.9971±1.1361,205.8992±13.0056;231.2814±2.4867,229.7843±0.6310,224.1654±4.1101;205.6065±5.3733,192.3025±5.2611,176.3303±3.2838,F=79.405,27.110,17.987,95.732,P<0.05)。②肝、脑、骨折周围肌肉组织内镍离子的含量:类金刚石镀膜镍钛合金环抱器组和髓内针内固定组镍离子含量低于非镀膜镍钛合金环抱器组[分别为(0.0428±0.0244),(0.1325±0.0065),(0.2330±0.5102)μg/g;(0.1314±0.0154),(0.1757±0.0129),(0.2186±0.0384)μg/g;(0.1313±0.0213),(0.1498±0.0079),(0.2058±0.0103)μg/g,F=83.854,30.379,72.510,P<0.05]。结论:弹性内固定有利于促进骨折愈合;类金刚石镀膜镍钛合金环抱器的组织相容性明显优于非镀膜镍钛合金环抱器。

AIM： To study the effect of coated and uncoated materials made by elastic nickel-titanium alloy internal fixator on healing of fracture, and compare the effect of continuous compressive stress after internal fixator of different types on healing of fracture by setting up bone nail internal fxation group. METHODS： The experiment was conducted in the Laboratory of Tissue Engineering, Institute of Orthopedics, Second Hospital Affiliated to Lanzhou University between September 2004 and March 2005. Thirty Qingzilan rabbits of 4-6 months old were randomly divided into 3 groups, Group A （diamond-like carbon coated nickel-titanium alloy embracing fixator group）, group B （uncoated nickel-titanium alloy embracing fixator group） and group C （intramedullary needle flxator group）, with 10 rabbits in each group. Transverse fracture model in middle part of the femur were made on each animal and fixed by diamond-like carbon coated nickel-titanium alloy embracing fixator, uncoated nickel-titanium alloy embracing fixator and intramedullary needle fixator respectively. The quality fraction of inorganic material, ostcalcin, alkaline phosphatase （AKP） and tumor necrosis factor （TNF） （A） in callus around fracture were detected 4 weeks postoperatively. Ni＋ in muscles around fracture, brain and liver were also detected. The differences in compatibility between nickel-titanium alloy and non-coating materials were evaluated, and the effect of continuous compressive stress on callus formation in the healing of fracture by different fixator was studied. RESULTS： A total of 30 enrolled animals were involved in the analysis of results, （1） Quantitative analysis and semiquantitative analysis of ostcalcin, AKP and TNF as well as the determination of inorganic material in callus around fracture： The quantity fraction of inorganic material, ostcalcin, AKP and TNF in group A and B were higher than those in group C （which were 0.285 ±0.007 2,0.251 7±0.009 9,0.178 6±0.031 4;228.832 4±1.595 2,225.997±1.136 1, 205.899 2±13.005 6;231.281 4±2.486 7,229.784 3±0.631 0,224.165 4±4.110 1 ;205.606 5±5.373 3,192.302 5±5.261 1, 176.330 3±3.283 8, F =79.405, 27.110,17.987,95.732, P 〈 0.05）.（2~） Ni^＋ in liver, brain and muscles around the fracture： It was lower in group A and C than that in group B [（0.042 8±0.024 4）,（0.132 5±0.006 5）, （0.233 0±0.510 2）μg/g;（0.131 4±0.015 4）,（0.175 7±0.012 9）, （0.218 6±0.038 4）μg/g; （0.131 3±0.021 3）, （0.149 8±0.007 9）, （0.205 8±0.010 3）μg/g, F =83.854, 30.379,72.510, P 〈 0.05]. CONCLUSION： Elastic fixation promotes the healing of fracture. Diamond-like carbon coated nickel-titanium alloy embracing fixator has a better histocompatibility than uncoated group.