聚乳酸棒对骨折愈合影响的实验研究

研究国产聚—DL—乳酸棒对骨折愈合的影响。建立尺桡骨骨折固定模型。右侧尺桡骨中外1／4双骨折用PDLLA棒髓内固定，对侧用克氏针固定作为对照。动物术后2、4、6、8、12周处死。作组织切片光镜观察以及骨折断端纵剖面的扫描电镜观察。组织学光镜观察示膜内成骨和软骨内成骨现象在骨折愈合过程中同时存在。12周时都已顺利愈合。但在同时间点，实验组成骨进程要比对照组的慢。电镜观察显示胶原纤维的生成，钙盐的沉积实验组较对照组慢。然而组织学及电镜所见到骨愈合过程中各阶段的细胞形态、钙盐沉积过程表现正常。说明成骨过程是正常的。PDLLA材料对骨折愈合过程有一定的延迟作用，临床上应用于血供丰富部位骨折固定。

Effect of Absorbable Poly-DL-lactide Rods on Experimental Fracture Healing

This study was designed to assess the effect of a home-bred poly-DL-lactide (PDLLA) rods on experimental fracture healing. An operation was performed to create bilateral ulnar and radial fractures of forearm in 15 rabbits. The right sides were fixed with 2 PDLLA (Mv = 34 x 10(4), 1.6 mm x 1.6 mm x 30 mm) rods, and the contralateral sides were fixed with 2 Kirschner wires to be used as controls. After operation, casts were used for external fixation, and the joint above and the joint below the fracture were immobilized. The casts were removed at the 6th week after operation. The specimens were removed at specific intervals between 2 and 12 weeks. Histologically, the light microscopy and scanning electron microscopy evaluation of the rabbit ulnar and radial fractures fixation revealed that, the fractured bone gradually healed and the PDLLA rods properly fixed on the fracture area during the implanted period. However, results suggest that internal fixation by absorbable material made the course of fracture healing slower than that in the control group, but the osteogenesis appeared to be normal. In the absorbable group, the collagenous fiber was characterized by order and orientation, and calcified normally. In conclusion, this kind of PDLLA rods have an effect on delaying the process of the normal union of fracture and should be applicable to fractures where the tissues are rich in blood supply.