羟基磷灰石/聚DL乳酸复合材料骨内植入界面观察

INTERFACE OBSERVATION OF HYDROXYAPATITE/POLY(DL-LACTIDE) COMPOSITES IMPLANTED INTO BONE TISSUE

目的 :评价自行研制的可吸收羟基磷灰石 /聚DL乳酸 (HA/PDLLA)复合骨折内固定材料的骨结合能力和刺激成骨能力。方法 :在兔股骨髁松质骨部作横行截骨后用一枚HA/PDLLA棒内固定 ,3,6,12 ,2 4 ,36周取材。结果 :组织学检查见材料周围明显新骨形成 ,在髁部材料与骨组织直接接触。扫描电镜见新骨表面有活跃的成骨细胞 ,HA与新骨直接结合。推出试验见材料骨组织界面剪切强度逐渐增加。结论 :HA与PDLLA复合后 ,使材料具有一定程度的骨结合能力 ,提高了材料的生物活性和刺激成骨能力 。

To evaluate bonebonding capability and osteostimulatory potential of selfdesigned absorbable fracture fixation devices made of hydroxyapatite/poly(DLlactide) (HA/PDLLA) composites, 43 rabbits with a transverse transcondylar osteotomy of distal femur were fixed intramedullary by a HA/PDLLA rod (diameter, 4.5mm; length, 30～40mm). The followup times were 3,6,12,24 and 36 weeks. Histologic, scanning electron microscopic and biomechanical analyses were done. Results: Histologically, considerable new bone formation were present around the implant as early as three weeks. Direct bony contact at the tissueimplant interface were seen at the cancellous spaces of the condylar. Scanning electron microscope analysis showed that generous HA crystals deposited and grew on the surface of the composites 3～6 weeks postoperatively. New bone formed by active osteoblasts was seen around the implant and HA particles were directly bonded to it. The pushout strengths at the interface were increased gradually. Conclusion: The selfdesigned HA/PDLLA composites also possessed some bonebonding capacity and osteostimulatory potential, which enhanced the bioactivity of the composites and was good for fracture healing.