预紧力作用下钛合金人工假体界面骨小梁形态参数测量与统计分析

Measurement and statistical analysis of trabecular morphological parameters of titanium alloy periprosthesis under preload

背景:钛合金人工假体植入后会产生应力遮挡,破坏该区域内骨组织的力学微环境,影响正常骨重建进程。采用过盈配合方式产生预紧力植入人工假体重建该区域内的力学微环境,达到保证术后中远期骨重建进程,具有重要的理论意义与临床应用价值。目的:分析预紧力对多孔钛合金人工假体骨整合的促进作用。方法:将14只雄性新西兰大白兔分为2组,实验组在右侧后腿股骨髁外侧以过盈配合方式植入1颗3D打印钛合金人工假体,对照组自由饲养,每组7只。术后12周取术侧股骨,进行micro-CT扫描及三维重建,测量假体区域骨密度与骨小梁组织形态学参数。动物实验方案已获天津市医药科学研究所动物伦理委员会批准,批准文号:IMPS-EAEP-Z-2019108-01。结果与结论:①实验组骨密度明显低于对照组(P<0.05);②实验组骨体积分数、平均骨小梁厚度及单位长度内平均骨小梁数量少于对照组(P<0.05),骨表面积比与骨小梁分离度大于对照组(P<0.05),两组骨小梁各向异性比较差异无显著性意义(P>0.05);③结果表明,预紧力可促进多孔钛合金人工假体的骨整合,但长入骨组织的结构特征与健康骨相比仍然较差,在术后中远期可能具有较高的骨折风险。

BACKGROUND:The implantation of titanium alloy prosthesis would produce stress shielding to damage mechanical microenvironment of bone tissue.This might affect normal bone remodeling process.Interference fit was used to generate preload to reconstruct mechanical microenvironment in this area.It may have important theoretical significance and clinical application value to promote bone remodeling in the mid-long-term after surgery.OBJECTIVE:To analyze the promoting effect of preload on osseointegration of porous titanium alloy prosthesis.METHODS:Fourteen male New Zealand rabbits were divided into two groups.The three-dimensional(3D)printed titanium alloy prosthesis was implanted into the outside of right femoral condyle with interference fit in experimental group(n=7).Rabbits in the control group(n=7)were feed free.Femurs at the surgery side were extracted at 12 weeks after surgery.Micro-CT scanning and 3D reconstruction were performed to measure bone density and trabecular morphological parameters around the prosthesis.Animal experiment was approved by Animal Ethics Committee of Tianjin Institute of Medical Science(approval No.IMPS-EAEP-Z-2019108-01).RESULTS AND CONCLUSION:(1)Bone mineral density was reduced significantly in the experimental group compared with the control group(P<0.05).(2)Bone volume fraction,trabecular thickness,trabecular number were reduced in the experimental group compared with the control group(P<0.05).Bone surface area ratio and trabecular separation were larger in the experimental group than those in the control group(P<0.05).There was no significant change in degree of anisotropy between the two groups(P>0.05).(3)The results showed that preload could promote osseointegration of porous titanium alloy prosthesis.However,the structural characteristics of the in-growth bone were worse than healthy bone.This might lead to a high fracture risk in the mid-long-term after surgery.