国产聚-DL-乳酸螺钉力学和生物降解吸收性能的实验研究

An animal study of mechanical strength and biological absorption and degradation of home-bred poly-DL-lactic acid screws

目的 探讨国产聚 -DL -乳酸 (PDLLA)螺钉的力学和生物降解吸收性能。 方法 用黏均分子量 (Mv)达 43× 10 4的PDLLA螺钉内固定 32只犬股骨外髁骨折 ,并以金属螺钉固定为对照。动物于术后 2 ,4,8,12周处死 ,行X线摄片、螺钉力学以及骨组织内PDLLA的生物降解率(BDR)、生物吸收率 (BAR)测定。 结果 PDLLA螺钉初始剪切强度为 74.74MPa,4周时为 48.71MPa ,8周时为 2 7.6 1MPa。 12周时 ,PDLLAMv为初始的 11% ,重量保持了 86 %。X线显示 12周后两组骨折均正常愈合。 结论 国产PDLLA螺钉不需取出 ,比金属螺钉更适用于负重或非负重松质骨骨折和关节内骨折。

Objective To investigate the mechanical strength and biological absorption and degradation of the home bred poly DL lactic acid screws. Methods An operation had been conducted to create bilateral and lateral femoral condylar fractures in 32 dogs. The left sides were fixed with 2 PDLLA (Mv=43×10 4) screws, and the contralateral sides fixed with 2 metalic screws were used as controls. The animals were sacrificed at 2, 4, 8, 12 weeks after surgery. Roentgenographic investigation, mechanical strength and biological absorption and degradation of PDLLA screws in bone tissues were done. Results The initial shear strength of PDLLA screws was 74.74 MPa, and decreased to 48.71 MPa after 4 weeks ,27.61 MPa by 8 weeks. By 12 weeks, the molecular weight of PDLLA had retained only 11% of the initial value, whereas 86% of the weight still remained. X ray showed that fractures in both groups had been united normally after 12 weeks. Conclusions This kind of home bred PDLLA screw is more suitably used in burden or nonburden cancellous bone fractures and intra articular fractures than the metalic ones.