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机械强度和生物降解性。方法：体外降解实验是把相同分子量的HA/PDLLA和单纯PDLLA试件分别置于PBS缓冲液中，于2、4、6、8、10、12周取材，测试生物降解率、吸水率、失重率、机械强度及降解液pH值，并作扫描电镜(SEM)观察；体内实验是用一枚HA/PDLLA棒内固定兔股骨髁松质骨部横形截骨，作X线摄片、组织学、机械强度及材料骨界面SEM观察。结果：HA/PDLLA复合材料较单纯PDLLA材料降解速度减慢，机械强度提高，骨折正常愈合。结论：HA/PDLLA材料具有足够的强度保证实验性松质骨骨折正常愈合。%The mechanical properties and biodegradation of self-designed hydroxyapatite/poly (DL-lactide) (HA/PDLLA)composites were investigated in vitro and in vivo. In vitro, the specimens of HA/PDLLA and unfilled PDLLA were immersed in phosphate-buffered saline. Ageing of various devices were monitored by measuring molecular weight, water absorption, weight loss, pH, mechanical strengths and microstructure changes. The follow-up times were 2, 4, 6, 8, 10 and 12 weeks. In vivo, a transverse transcondylar osteotomy of the distal femur was fixed with a HA/PDLLA rod (diameter, 4.5mm; length, 30～40mm). The follow-up times were 3, 6, 12, 24 and 36 weeks. Roentgenographic, histologic, biomechanical and scanning electron microscopic studies were done. The results showed that HA/PDLLA composites had higher mechanical strength and slower degradation speed than unfilled PDLLA, all osteotomies united within six weeks without delay. Consequently, the HA/PDLLA composites possessed sufficient mechanical strength for the fixation of cancellous osteotomies.
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