Musculoskeletal+ Biomechanics + BIOEN+520+|+ME+527+ Session+9A + Biomechanics + of+Bone + …Structure,)Func,on, ) and)Proper,es )
Bone...+ [Q]: +What+do+we+know+about+bone?+
Jeopardy…+ Bone $200 $400 $600 $800 $1000
Jeopardy...+ 206 + What+is+the+(average)+ number+of+bones+in+the+ adult+human+body?+
Jeopardy…+ Bone 206 $400 $600 $800 $1000
Jeopardy...+ Support,+protect,+homeostasis,+ hematopoiesis… + What+is+the+funcSon+of+bone?+
Jeopardy…+ Bone 206 Support, protect, ... $600 $800 $1000
Jeopardy...+ CorScal+and+Cancelleous… + What+are+the+ two+primary+ types+of+bone?+
Jeopardy…+ Bone 206 Support, protect, ... Cortical and Cancellous $800 $1000
Jeopardy...+ Osteoblasts,+osteoclasts,+ osteocytes… + What+are++++++ + the+types+of+ bone+cells?+
Jeopardy…+ Bone 206 Support, protect, ... Cortical and Cancellous Osteoblasts, osteoclasts, ... $1000
Jeopardy...+ This+German+anatomist+developed+ the+theory+on+the+funcSonal+ adaptaSon+of+bone.++ Who+is+Julius+ Wolff?+
Session+9A+Discussion+QuesSons...+ [Q]:+What+is+the+mechanical+funcSon+of+bone?+ [Q]:+What+is+the+structure+(macro/micro)+of+bone?+ [Q]:+How+do+the+mechanical+properSes+of+bone+ compare+to+other+materials?+ [Q]:+How+does+the+structure+of+bone+relate+to+its+ funcSon+and+properSes?+ [Q]:+Why+should+we+care+about+the+properSes+of+ bone+(…how+could+they+help)?+
Bone:+B y+the+ N umbers …+ Bones+by+Region+ 28+]+Head/Face/Ear+ 26+]+Chest+(ribs,+ 64+]+Upper+Extremity+ sternum,+and+ hyoid)+ 26+]+Spine+ 62+]+Lower+ ExtremiSes+
Bone:+M acrostructure ...+ [Q]: +What+and+where+are+the+general+regions+ of+long+bones?+ • Epiphysis:++ trabecular bone w/ cortex • Physis:+ growth plate • Metaphysis:+ trabecular bone w/ cortex • Diaphysis:+ cortical bone (shaft) • Periosteum:+ fibrous membrane
Bone:+M acrostructure ... + Examples:+
Bone:+Microstructure...+ [Q]: +What+is+the+fundamental+structural+unit+ of+corScal+bone?+ Osteon+
Bone:+M icrostructure ... + Mow+and+Hayes+(1997)+
Bone:+C orScal … ++ +Compact+bone+composed+of+ Sghtly+packed+osteons+ ! Osteon+Dia.:++100]300+ µ m+ ! Density:++1.7]2.0+gm/cc+ ! Volume+FracSon:+85]90%+ Jee+(1983)+
Bone:+C ancellous +/+T rabecular …+ +Porous+“spongy”+bone+ ! Trabeculae:++100]300+ µ m+(thick)+ x+600]1000+ µ m+(long)+ ! Density:++0.09+to+1.26]g/cc+ ! Vol.+FracSon:+~25]30%+(young)+ ! High+surface+area+to+volume+ raSo+ Yeh+and+Keaveney+(1999),++Jee+(1983)+
Bone:+TesSng...+ [Q]: +How+would+you+prepare+and+test+bone+ samples?+ Garnier+(1999),+Mimon+(1997)++
Bone:+TesSng...+ Cancellous+Bone...+ Mimon+(1997),+Garnier+(1999)+
Bone:+TesSng...+ +CorScal+ Bone...+ Kemper+(2007)+
Bone:+TesSng...+ +NaSve+ Metacarpal+in+ 3]pt+bending+ Wam+(2014)+
Bone:+P roperSes ...+ support & protect... ! [Q]: + To+fulfill+its+role,+what+kind+of+mechanical+ properSes+does+bone+have?+ Comp. Stress (MPa) ( ⊥ grain )
Bone:+P roperSes ...+ [Q]: +Does+fiber+orientaSon+affect+properSes?+ Yes!+
Bone:+P roperSes ...+ [Q]: +Is+bone+strain]rate+sensiSve?+ Yes!+
Bone:+P roperSes ...+ Typical+Values...+ Cortical Trabecular Modulus 15-20 GPa 0.2-0.5 GPa Compression Strength 150-200 MPa 2-10 MPa Modulus 10-15 GPa 0.2-0.5 GPa Tension Strength 100-150 MPa 2-10 MPa Modulus 2-5 GPa ? Shear Strength 50-75 MPa 2-10 MPa Mow+&+Hayes+(1997),+Kopperdahl+and+Keaveney+(1998),++Ciarelli+(1991)+
Bone:+C omposiSon ...+ [Q]: + What+in+the+composiSon+(structure)+of+ bone+would+give+it+these+properSes?+ ! Extracellular+matrix...+(2+phases)+ • Organic+phase:+Collagen++++++++++++++++++++++++++++++++++++++ (50]60%+of+bone+vol.,+25]35%+of+bone+wt.)+ • Mineral+phase:+HydroxyapaSte+crystals+++++++++++++ (40]50%+of+bone+vol.,+65]75%+of+bone+wt.)+ ! A+“bio]composite”+material…+ Mow+and+Hayes+(1997)+
Bone:+S tructure ]F uncSon ]P roperty ...+ [Q]: + In+summary,+how+does+the+structure+of+ bone+relate+to+its+properSes+and+funcSon?+ Its structure (a strong bio-composite material) and properties (stiff and strong) enables it to perform its necessary function (support the weight of the body and protect vital organs)… FuncSon+ Structure+ Property+
Bone:+Summary...+ • +A+biological+“living”+Sssue+(…not+staSc)+ • +Two+primary+types:+corScal+and+trabecular+ • +A+“bio]composite”+material+consisSng+of+ organic+(collagen)+and+mineral+(HA)+phases+ • +RelaSvely+strong+and+sSff+and+remodels+in+ response+to+funcSonal+loads+ • +Fiber+orientaSon+results+in+different+properSes+ for+different+loading+direcSons+(anisotropic)+ • +ViscoelasSc+(strain]rate+dependent)++
Bone:+T est+ C onsideraSons ... + [Q]: + What+factors+should+be+considered+when+ tesSng?+ • Storage+/preservaSon+ • Temperature+ • HydraSon+ • Sample+size+and+type+ • Strain+rate+ • Mode+of+loading+ • OrientaSon+ • Age/gender+
Bone:+Why+Study? + [Q]: + Why+should+we+care+about+the+properSes+ of+bone?+ Need+naSve+properSes+for:+ • Medical+device+development+ • SubsStute+materials+(bone+grass/fillers)++ • Tissue+engineering++
Bone:+Case+Study+#1+ (Bone+gras+subsStute)+ Bone+Gras+Materials:+ • Autograph+Bone+ • Allograph+Bone+ • Ceramics+ • Polymers+ PolyGraft, OsteoBiologics, Inc.
Bone:+Case+Study+#1+ (Bone+gras+subsStute) + Interpore+Pro+Osteon...+ - Coralline hydroxyapatite (Similar composition and pore structure) - Biocompatible - Sterilizable " Properties??? hmp://www.interpore.com+
Bone:+Case+Study+#1+ (Bone+gras+subsStute)+ Smaller pore size... Interpore+Pro+Osteon + [VF = 31.4 ± 2.0%] Femoral+Trabecular+Bone + [VF = 29.8 ± 0.4%] Vertebral+Trabecular+Bone + [VF = 14.2 ± 1.5%]
Bone:+Case+Study+#1+ (Bone+gras+subsStute)+ Vertebral+ Property + Pro+Osteon + Femoral+Bone + Bone + Modulus+[Mpa] + 2900+±+1290 + 441+±+271 + 309+±+109 + Strength+[Mpa] + 5.87+±+1.92 + 6.76+±+4.84 + 2.23+±+0.95 + UlSmate+Strain + 0.0022+±+0.03 + 0.011 + 0.019 + Permeability+ 0.49+±+0.19 + 0.12+±+0.11 + 3.59+±+1.90 + [ x 10 ]9 m 2 ] + [Haddock+et+al,+1999]+
Bone:+Case+Study+#1+ (Bone+gras+subsStute)+ Summary: - Stiff (…6x bone) - Dense (...smaller pore size) - Brittle (...low ultimate strain) - Permeability (...ok) Pro+Osteon+in+canine+ Okay for some applications... humeri+(3,+6,+12,+and+24+ weeks) Not well matched for vertebral trabecular bone... [Resnick,+2002]+
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