羟基磷灰石复合聚乳酸可吸收螺钉的力学及生物降解性

摘要

BACKGROUND:Through compounding hydroxyapatite and poly-DL-lactide, the mechanical properties, physical and chemical properties of the implants can be enhanced. OBJECTIVE:To detect the effect of hydroxyapatite/poly-DL-lactide composite internal fixation screws in canine femoral condyle cancel ous bone fracture repair. METHODS:Forty-two beagle dogs were operated to bilateral femoral condyle fracture models. The left side was fixed using hydroxyapatite/poly-DL-lactide screws as experimental group;while the right side was fixed with pure poly-DL-lactide screws as control group. After 2, 4, 8, 12, 24, 36 and 48 weeks, conditions of fracture were observed using X-ray, femoral and screw specimens were observed histopathological y, and the bending strength and the average molecular weight were detected. The biological absorption rate, intensity decay rate and biodegradation rate were calculated. RESULTS AND CONCLUSION:After 2-48 weeks, bilateral fractures were fixed wel and new bone grew wel , but the biological absorption rate of the screws in the experimental group was lower than that in the control group (P ≤0.01). In the first 2, 4 weeks, the bending strength of the experimental screws was higher than that of the control screw (P ≤0.05), but the biodegradable speed was slower in the former one (P ≤ 0.05 or P ≤ 0.01). The pathological changes were similar in the two groups. After 48 weeks, the fractures were healed and bone tissue reconstruction was completed. Compared with the pure poly-DL-lactide screws, the hydroxyapatite/poly-DL-lactide composite internal fixation screws have better fixation effects, biocompatibility, mechanical properties and biodegradability.%背景：将聚乳酸与羟基磷灰石复合可提升植入体的力学性能、理化性能。　　目的：应用犬股骨外髁骨折内固定模型，观察羟基磷灰石复合聚乳酸骨折内固定螺钉修复股骨外髁松质骨骨折的效果。　　方法：手术制备42只比格犬双侧股骨外髁骨折模型，左侧采用羟基磷灰石复合聚乳酸可吸收螺钉内固定作为实验组，右侧采用单纯聚乳酸螺钉内固定作为对照组。置入后2，4，8，12，24，36，48周获取标本，X射线观察骨折恢复情况，取股骨和螺钉标本进行病理组织学观察，检测螺钉质量、抗弯强度和重均分子质量，计算生物吸收率、强度衰减率和生物降解率。　　结果与结论：置入后2-48周，双侧骨折区内固定良好，新骨生长良好，实验组螺钉生物吸收率低于对照组(P ≤0.01)。实验组置入后2，4周螺钉抗弯强度高于对照组(P ≤0.05)，置入后2-48周螺钉生物降解率低于对照组(P ≤0.05或P ≤0.01)。两组标本病理变化相似，置入后48周，骨折均愈合，骨组织重建良好。表明羟基磷灰石复合聚乳酸可吸收螺钉具备良好的内固定疗效和生物相容性，其力学性能和生物降解性能优于单纯聚乳酸螺钉。