羟磷灰石涂层钛合金植入材料的理化参数、生物相容性及其力学特征

背景羟磷灰石涂层人工关节具有骨长入生物固定作用而能与宿主床骨紧密联结,从而解决人工关节下沉问题.目前临床上最常用的羟基磷灰石(HA)涂层材料主要使用的是等离子喷涂法所制.这种制备方法因为高温,使HA不可避免地产生晶相结构改变,从而使HA的生物活性大为下降,直接影响假体与骨之间的结合.目的通过涂覆工艺研制出一种新的含羟磷灰石玻璃涂层钛合金多孔涂复材料.本实验对该材料进行了理化参数、生物相容性及其力学特征的测定,为该材料在临床的应用提供实验依据.设计随机分组,自身对照实验研究.地点和对象研究在上海市伤骨科研究所完成.48个HA表面涂层及非涂层钛合金材料由轻工业部玻璃塘瓷工业科学研究所制备.干预①测定材料的最佳烧结温度、机械强度,观察材料表面的多孔结构.②取24只新西兰种家兔,在两侧股骨外髁上共植入48个HA表面涂层及非涂层钛合金材料,分别于术后1,2,3,6及12周处死取材.测定骨-HA界面最大剪切强度并作组织学观察.主要观察指标①材料最佳烧结温度、机械强度.②材料表面多孔结构、切片组织学观察.③骨-HA界面的最大剪切强度.结果测出材料的最佳烧结温度为800℃,抗剪强度为18.5 MPa,抗压强度为170 MPa,孔隙率10%～15%,孔径30～70μm.HA涂层钛合金组能与宿主骨紧贴,新骨能迅速长入材料的裂隙和被降解的封闭小孔内,而非涂层材料能使新生骨组织死亡并为结缔组织取代.在术后任一时间段涂层材料骨-HA界面最大剪切强度均明显高于非涂层组.(术后3周均差=0.86,t=15.61,P＜0.01;术后6周均差=1.72,t=18.19,P＜0.01;术后12周均差=4.42,t=12.84,P＜0.01)结论这种新材料能作为人工骨或人工关节材料应用于临床.

Physicochemical parameters, biocompatibility and mechanical characters of hydroxyapatite coated on titanium alloy implant

BACKGROUND: Hydroxyapatite(HA) coated artificial joint has the property of bone ingrownths fixation presented by intimate ossteointegration with host bedbone, thereby avoiding possible joint subsidence. Commonly used HA coating was deposited mainly by thermal plasma-sprayed process,which inevitably led to change of crystallinity of HA and consequently decreased bioactivity, directly affecting the oseeointegration of artificial joint.OBJECTIVE: To develop a novel porous surfaced titanium alloy coated by HA glass coatings processed with spraying technique. Physiochemical parameters, biocompatibility and mechanical characters were studied to provide experimental basis for future clinical application.DESIGN: A randomized auto-controlled trial.SETTING and SUBJECTS: This study was completed in Shanghai Orthopaedic Research Institute. Forty-eight sets of HA coatings and uncoated titanium alloy substance were prepared by glass-ceramic Industrial Science Iinstitute of Light Industrial Ministry.INTERVENTION: To investigate the optimal sintering temperature, mechanical strength and porous surface microstructure of composite coatings.Totally 48 sets of HA coated and uncoated-Ti-Alloy were implanted at bilateral femoral outer condyle in 24 New Zealand rabbits who were then put to death at 1, 2, 3, 6, 12 weeks postoperatively for taking specimen. The maximum shear strength at bone-HA interface and histological changes were investigated.RESULTS: The optimal sintering temperature was 800 ℃, anti-shearing strength and pressure resistant strength was 18.5 MPa and 170 MPa respectively, aperture rate ranged from10% to 15% with diameter of 30 -70 μm. HA-Ti-Alloy coatings could tightly bond to host bones, which benefit for newly formed bone ingrowing into the crannies and dissolved blocked mesh, meanwhile non-coated substance provided micromelium for connective tissue replacing the died newly formed bone. Shear strength of bone-HA interface was obviously higher than that of non-coating group at any postoperative intervals. (postoperative 3 weeks MD =0. 86, t = 15.61, P ＜ 0.01;postoperative 6 weeks MD = 1.72, t = 18. 19, P ＜ 0. 01; postoperative 12weeks MD=4.42,t=12.84,P ＜0.01).CONCLUSION: This new material could be used in clinical practices as coatings on artificial bone or joint.