交叉使用不锈钢和钛合金固定骨折后远期周围组织反应的比较

Long-term tissue reactions following fracture internal fixation with crossing application of stainless steel versus titanium alloy

背景:目前多认为不锈钢或钛合金材料的交叉会引起严重的电解蚀损,国内外研究不锈钢和钛合金材料交叉固定骨折多停留在从体外模拟人体体液内环境,或者是从冶金学、化学角度来具体检测金属内植入物有没有蚀损。目的:尝试通过动物体内实验,观察不锈钢或钛合金材料单独和交叉组合固定骨折的电解蚀损情况及其对骨折愈合的影响。设计、时间及地点:随机对照动物实验,于2007-09/2008-09在山西医科大学动物实验中心及中心实验室完成。材料:选择健康成年新西兰大白兔32只。方法:将32只新西兰大白兔按随机数字表法分为4组,即钛板+钛钉组、不锈钢板+不锈钢钉组、钛板+不锈钢钉组、不锈钢板+钛钉组,每组8只。麻醉后在各组新西兰兔一侧胫骨中段处用线锯截骨,按上述不同组合内固定,不做任何外固定。主要观察指标:在内固定后12,26,39,52周末,检测动物内固定周围软组织炎细胞浸润情况及包膜厚度,以免疫组织化学法检测内固定周围软组织包膜中细胞增殖核抗原的表达,应用超声骨强度仪测量骨折部位的超声速度,以评价骨折愈合状况。结果:在内固定后12,26,39,52周,钛板+钛钉组及钛板+不锈钢钉组内固定周围软组织炎性细胞数量及包膜中细胞增殖核抗原阳性表达率均显著低于不锈钢板+不锈钢钉组及不锈钢板+钛钉组(P<0.05),包膜厚度显著小于不锈钢板+不锈钢钉组及不锈钢板+钛钉组(P<0.05)。钛板+钛钉组与钛板+不锈钢钉组,不锈钢板+不锈钢钉组与不锈钢板+钛钉组之间差异无显著性意义(P>0.05)。骨折部位的超声速度显示不同组合对骨折愈合无明显影响(P>0.05)。结论:远期生物相容性钛合金组优于不锈钢组,交叉组合与未交叉组合无明显差异,均不影响骨折愈合。

BACKGROUND： Crossing application of stainless steel or titanium material is considered to induce severe electrolysis erosion. Most of studies regarding crossing application of stainless steel or titanium material focus on erosion of the metal implants in simulated human humoral environment or by metallurgy or chemistry. OBJECTIVE： To investigate the electrolysis erosion and the effects of crossing application of plates and screws made of stainless steel or Ti-6AL-4V （Ti） in the internal fixation on rabbit fracture healing. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment was performed at the Animal Experimental Center and Central Laboratory of Shanxi Medical University between September 2007 and September 2008. MATERIALS： A total of 32 healthy adult New Zealand rabbits were selected. METHODS： The experimental rabbits with tibia fracture were randomly divided into four groups with 8 animals in each group. They were fixed with the different combinations of plates and screws made of stainless steel or Ti respectively： combination of Ti plates and Ti screws; combination of steel plates and steel screws; combination of Ti plates and steel screws; combination of steel plates and Ti screws. No external fixation was performed MAIN OUTCOME MEASURES： At the end of 12, 26, 39 and 52 weeks after internal fixation, inflammatory cell infiltration of soft tissues surrounding the internal fixation was detected; expression of proliferating cell nuclear antigens （PCNA） was determined by immunohistochemistry; speed of sound （SOS） at the fracture site was determined to evaluate fracture healing condition. RESULTS： After 12, 26, 39, 52 weeks of the operation, quantity of inflammatory cells and positive rate of PCNA in Ti plate and Ti screw group and Ti plate and steel screw group were significantly less than the other groups （P 〈 0.05）; the thickness of fibrous capsule was smaller than steel plate and steel screw group and steel plate and Ti screw group （P 〈 0.05）. There were no significant differences between Ti plate and Ti screw group and Ti plate and steel screw group or between steel plate and steel screw group and steel plate and Ti screw group （F＇ 〉 0.05）. The SOS showed that the different combinations of internal fixation materials had little influence on the healing of fractures （P 〉 0.05）. CONCLUSION： Long-term biocompatibility of titanium alloy is better than stainless-steel, and there are no significant differences between crossing group and non-crossing group, which do not affect the healing of fractures.