复合人工髋关节骨结合区力学行为的有限元分析

The Biomechanical Behavior Analysis in the Host-donor Junction Area of Allograft Hip Joint Composite by FEA

同种异体骨复合人工髋关节置换术后不同时期,人工髋关节、骨水泥及其周围骨,特别是宿主骨和异体骨结合区的生物力学数据是复合关节设计、手术及术后康复训练方案制定的重要依据之一。基于患者的CT扫描数据,建立复合人工髋关节移植治疗股骨近端骨缺损的三维有限元模型,选用1.5倍、2.5倍70Kg标准体重进行生理加载,计算术后结合区骨愈合3个阶段的力学性质。结果表明,术后初期,结合区弹性模量较低,在其中部及周围骨水泥中有较严重的应力集中,骨水泥中的最大应力超过了其抗压强度,存在失效风险;随着结合区的愈合,结合区组织由骨痂发展为自然皮质骨,组织的弹性模量逐渐增高,结合区中的应力屏蔽得到改善,骨水泥中的应力集中同时得到缓解,并最终接近自然骨。采用多孔羟基磷灰石生物陶瓷(HA)作为骨组织支架材料充填结合区,可有效降低结合区的应力屏蔽,提高其力学安全性。

Based on the CT data of a patient＇s femur,a three-dimensional FEA medical model of femur treated with AHJC was rebuilt,under the load conditions of 1.5 and 2.5 times standard body weight （70 kg）,and the biomechanics of the model were analyzed for three different healing periods by FEA.The results showed that in the initial period post-operation,the Young＇s modulus of tissue in host-donor junction area was low,and there were serious stress concentrations in the middle of junction area and the bone cement,meanwhile,the maximum stress in bone cement was higher than the compress strength of it,so it would be in the risk of crash.With the growth of new bone in host-donor junction area,the Young＇modulus of the tissue increased,and the stresses shielding and concentration in the junction area and bone cement decreased greatly.The stress distribution in host-donor junction area will be in the level of normal bone,after the wound healed and the tissue in host-donor junction area gradually grew to be mature bone.Porous hydroxyapatite （HA） ceramics used as bone-scaffold in the host-donor junction area would decrease the stress shield and concentration in the junction area,and improve the biomechanical safety properties for clinic application of the AHJC.