二氧化钛涂层外固定支架钛螺钉预防钉道感染的实验研究

目的评估二氧化钛涂层螺钉的抑菌能力，观察其用于外固定支架对骨折钉道感染的治疗效果。方法制备二氧化钛涂层螺钉, 体外进行抑菌实验。新西兰大耳白兔30只，随机分为钉道(MO)组和二氧化钛涂层螺钉(TG)组各15只，建立骨折合并钉道感染模型，术后定期分别摄X片、拍照、取材进行HE染色，细菌培养和计数。结果TC组的抑菌圈半径为(2.96±2.86)cm，大于TS组(33.96±6.10)cm(P < 0.01)。术后1 d、1周和4周MO组软组织炎性评分均高于TG组(P < 0.05~P < 0.01)。术后1 d细菌数(对数值)2组差异无统计学意义(P>0.05)；术后1周和4周TG细菌数量(对数值)均较MO组下降(P < 0.01)。术后1 d、1周、4周，MO组均有大量炎性细胞浸润且逐渐增多，而TG组仅见少量炎性细胞浸润；MO组均表现为部分骨组织螺纹破坏吸收；TG组则均表现为钉道螺纹清晰无破坏及吸收。X线示，TG组1周时骨折线开始模糊，而MO组骨折线仍较清晰；4周时，TG组骨折端已达骨性愈合，MO组骨折端位移仍较明显，未达骨性愈合。结论二氧化钛涂层螺钉有光催化杀菌作用，用于外固定支架可有效预防骨折钉道感染。

Study on the external fixator of titanium dioxide-coated screw in preventing pinhole infection

Objective To evaluate the antibacterial activity of titanium dioxide-coated screw, and observe its effects on pinhole infection in external fixator treating fractures.Methods Titanium dioxide-coated screw was prepared, and its antibacterial experiment was performed in vitro.Thirty New Zealand white rabbits were randomly divided into the pinhole group(MO group) and titanium oxide-coated screw group(TG group)(30 rabbits each group).A fracture complicated with pinhole infection model was established.Two groups were treated with taking X-ray, taking photo, harvesting materials for HE staining, culturing bacteria and counting.Results The bacteriostatic radius in TG group(2.96±2.86)cm] was greater that in MO group(33.96±6.10)cm] (P < 0.01).The inflammation scores of soft tissue in MO group after 1 d, 1 week and 4 weeks were higher that in TG group(P < 0.05 to P < 0.01).The difference of bacteria count after 1 d of operation between two groups was not statistically significant(P>0.05), which in TG group after 1 week and 4 weeks of operation decreased compared with the MO group(P < 0.01).A large number of inflammatory cells infiltrated, and gradually increased in MO group after 1 d, 1 week and 4 weeks of operation, and a few inflammatory cells infiltrated in TG group.Partial bone tissue with thread destroy absorption in MO group, and pinhole with clear and no damage and absorption in TG group were identified.At the first week, X-ray findings showed that fracture line began to blur in TG group, while fracture line in MO group remained clear.At the fourth week, the fractures in TG group had reached the bony union, and the displacement of the fracture end in MO group was still obvious and did not reach bony union.Conclusions Titanium dioxide-coated screw has a photocatalytic bactericidal effect, which can effectively prevent the pinhole infection in external fixator treating fracture.