羟基磷灰石(HA)复合聚乳酸(PDLLA)可吸收螺钉修复犬股骨骨折的实验研究

Experimental study of hydroxyapatite composite polylactic acid absorbable screws in canine femoral condyle fracture

目的本动物实验采用比格犬股骨骨折内固定模型,考察迪康可吸收聚乳酸(PDLLA)骨折内固定螺钉对股骨外髁松质骨骨折修复的影响。方法 42只比格犬随机分为7组,分别为术后2、4、8、12、24、36、48周,每组6只动物。手术复制股骨外髁骨折模型,左侧(实验组)采用可吸收复合螺钉内固定,右侧采用PDLLA骨折螺钉内固定。术后各时间段处死受试犬,X摄片观察骨折恢复情况,解剖取股骨和螺钉标本进行病理组织学观察,同时检测螺钉质量、抗弯强度和重均分子量,计算生物吸收率、强度衰减率和生物降解率。结果实验结果显示术后2周时所有动物关节功能基本恢复正常,可吸收复合螺钉和PDLLA螺钉治疗的功能恢复无明显差异;可吸收复合螺钉的初始抗弯强度及植入前12周时高于PDLLA螺钉,生物降解较PDLLA螺钉缓慢。结论实验提示可吸收复合螺钉具备良好的内固定疗效和生物相容性,其在力学性能和生物降解性能方面较PDLLA螺钉具备一定优势。

Objective To detect hydroxyapatite composite poly-lactic acid fracture fixation screw in canine femoral condyle cancellous bone fracture repair.Methods 42 beagle dogs were randomly divided into 7 groups,and operated to bilateral femoral condyle fracture model.The experimental group（left） using hydroxyapatite composite polylactic acid screws fixed the control group（on the right） with pure poly lactic acid screw fixation.After 2、4、8、12、24、36、48 weeks,conditions of fracture were observed by X radiography,femur and screws specimens were observed by histopathological section,the bending strength and the average molecular weight were calculate too.Results 2 weeks after,functional recovery of the experimental group and the control group therapy was no significant difference;in the first 12 weeks,bending strength of the experimental screws were higher than the control groups,but implanted biodegradable speed were slower than the control groups.Conclusion Compared to polylactic acid screw,hydroxyapatite composite polylactic acid fracture fixation screw has superior mechanical properties and biodegradability.