骨科及康复生物力学.ppt

《骨科及康复生物力学.ppt》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、骨科及復健生物力學1骨小樑結構2Wolff’slaw˙Formfollowsfunction˙Bonehastheabilitytoadapt,bychangingitssize,shape,andstructuretothemechanicaldemandsplacedonit˙Boneislaiddownwhereneededandresorbedwherenotneeded˙Theremodellingmaybeeitherexternal(achangeintheexternalshapeofthebone)or(a

2、changeintheporosity,mineralcontent,anddensityofbone)3StructuralAdaptation4生物力學巨觀→微觀形態(Morphology)功能(Function)巨觀力學→微觀力學5有限元素法σ=CεF=KxK：stiffnessmatrixViscoelasticmodelσ=μdε／dtμ：viscositycoefficient6緻密骨(CorticalBone)組成：osteon,collagen,calcifiedtissue成骨細胞(osteoblaset)

3、蝕骨細胞(osteoclast)骨母細胞(osteocyte)細胞力學(CellMechanics)7海綿骨(CancellousBone)材料(material)及結構觀點(structure)材料性質：E結構性質：KTrussBarBeam8材料性質各向同性(Isotropic)OnlyoneE(K…)σ=Eετ=GγShearmodulusG=E/2(1+ν)AnisotropicStiffnessmatrixSizeeffectofMechanicalproperties9力學力(Force)變形(Deformati

4、on)PrincipalstrainStrainenergy應力(Stress)Principalstress10骨折癒合(FractureHealing)11骨折癒合(FractureHealing)12BiologyofFractureHealingThefracture(~7daysafterinjury)Thegranulationtissuestage(~twoweeks)Thecallus(4~16weeks)Theremodelingprocess(1~4years)Themodelingstage(oneor

5、moreyears)Theregionalacceleratoryphenomenon(RAP)13BoneRemodelingTheA–R–FsequenceA:ActivationR:ResorptionF:Formation14BoneModelingA-ForA-R15MechanicalAdaptationRemodeling:A-R-FModeling:A-ForA-R16骨折癒合(FractureHealing)17ConceptofInterfragmentaryStrain(ε)Perren&Cordey˙

6、Thetypeoftissueatthefracturegapcorrespondswiththedegreeofstrain˙Fracturehealingisaccompaniedbyasuccessivedecreasesofinterfragmentmotion˙Moresuitableforgaporcontacthealingmechanism18骨折癒合(FractureHealing)ε:Interfragmentarystrain19骨折癒合(FractureHealing)20骨折癒合Thehydrost

7、aticpressureisrepresentedas:Theoctahedralshearstressisgivenas:21骨折癒合22OsteogenicIndexwhereIisthescalarvalueoftheindex,iisagivenloadcase,cisthetotalnumberofdifferentloadcases,niisthenumberofloadingcyclesforagivenloadcase,Siisthecyclicoctahedralshearstress(alwaysposi

8、tive),Diisthecyclichydrostaticstress(negativeifcompression,positiveiftension),andkisanempiricalfactorweighingtherelativecontributionsofhydrostati