老年与青年股骨头内松质骨结构三维图像重建及力学性能测试研究

A comparative study of biomechanical strength and three-dimension structure image reconstruction of cancellous bone in femoral head between old and young people

目的 研究老年与青年股骨头松质骨的三维立体结构及力学性能。方法 取股骨头标本 38只 ,分成老年组 2 0例 ,年龄在 6 5～ 78岁之间 ;青年组 18例 ,年龄在 18～ 2 9岁之间。在股骨头致密区 (负重区 )和稀疏区 (非负重区 )各截取软骨下 3mm处 7mm× 7mm× 5mm松质骨各一块作松质骨结构的计算机三维图像重建研究。在股骨头致密区 (负重区 )用环钻纵向钻取软骨下 3mm处直径 8mm、高 10mm的松质骨柱 ,用以松质骨力学性能测试。结果 重建后的三维立体图像老年组较青年组明显稀疏 ;青年组松质骨试件的弹性模量、能量吸收、屈服强度、极限强度和极限应变等六项指标均明显高于老年组 (P <0 0 1～ 0 0 0 1)。两组干重骨量有显著性差异 (P <0 0 5 ) ,表观密度也有显著性差异 (P <0 0 5 )。结论 老年人松质骨的结构质量和骨量均比青年人低 ,其股骨头松质骨力学强度明显下降 。

Objective To study the biomechanical strength and three dimension structure image reconstruction of cancellous bone in femoral head between old and young people.Methods Thirty eight fresh femoral heads were divided into the elderly ( n= 20,age range between 65～78 years)and young( n= 18,age range between 65～78 years)groups.The cancellous bones(7mm×7mm×5mm)were taken from 3mm below the cartilage in the density and porotic region of the femoral head for the study of three dimension trabeculate structure image reconstruction of cancellous bone with computer;Cancellous bone biopsies (size:8mm,L10mm)obtained with a trephine from the density region of the femoral head 3mm under the cartilage were tested for biomechanical strength.Results The three dimensional images of trabeculate structure of cancellous bone were more porotic in elderly groups than in young groups.Modulus of elasticity,yield strength,ultimate strength and limiting strain in young group were significantly higher than those in elderly group ( P< 0 01～0 001).The dry weight and apparent density of cancellous bone in young group were also significantly higher than those in young group( P< 0 05).Conclusion This study suggests that elderly peoples might suffer more or less from osteoporosis resulting in a decrease in biomechanical strength of cancellous bone.It is one of the causes of frequent fractures.