front 1 Trabecular Bone Locations  back 1 Epiphyses and metaphyses

front 2 Trabecular vs Cortical Bone
 back 2 Typical bone volume fraction: 0.850.95 (Cortical), 0.050.6 (trabecular)

front 3 Trabecular Rods and Plates  back 3 Network of Rodsopen cell structure, lower density, regions of lower stress, located between condyles

front 4 trabecular remodeling  back 4 coupled bone resorption followed by bone formation at the same site 
front 5 osteoblasts  back 5 bone forming cells

front 6 osteoclasts  back 6 bone resorbing cells

front 7 osteocytes  back 7 inactive osteoblasts surrounded by bone matrix

front 8 osteoid  back 8 flat single nucleus unmineralized organic matrix components of bone that are deposited osteoblasts 
front 9 mechanical properties of trabecular bone (stressStrain)  back 9 Compression of a bone cube is similar to a cellular solid

front 10 Studies to determine mechanical properties of trabecular bone  back 10 Gibson (1985) Compression of a bone cube is similar to a cellular solid, stressstrain curve

front 11 compression properties of trabecular bone dependence  back 11 results of compression testing are dependent on:

front 12 wolff's law  back 12 Bone of high stiffness and strength is found in regions of high loads

front 13 Fracture risk equation  back 13 Risk=expected load from and activity/(load causing failure experimentally)

front 14 regression analysis  back 14 Predictive power depends on strength of correlation between two variables

front 15 variables considered to predict fracture risk  back 15 scalar variablesdensity (apparent), bone volume fraction, porosity

front 16 scalar variables to predict fracture risk  back 16 “Density”

front 17 clinical density measures  back 17 'bone mineral density" (BMD)

front 18 Dualenergy radiography (DEXA)  back 18 Reduced xray exposure

front 19 QCT density  back 19 Computed tomography

front 20 bone mineral density (BMD)  back 20 can be measured via QCT density and DEXA scans

front 21 operational definition of osteoporosis  back 21 BMD measured by DEXA is the refernece standard for osteoporosis diagnosis: Tscore < 2.5 (2.5 SD below mean of premenopausal women)

front 22 factors that increase the risk of fracture  back 22 age

front 23 fracture prevention strategies  back 23 Applied load/ bone strength

front 24 influences on bone strength  back 24 Bone mass

front 25 effects of again/osteopenia on trabecular structure  back 25 Decreases in

front 26 microarchitectural changes in osteoporosis  back 26 osteoporotic bone has a decrease in mass and number of trabeculae, and abnormalities in architecture compared to normal 
front 27 architectural variables  back 27 trabecular plate number (trabeculae per unit length, always more vertical than horizontal)

front 28 trajectorial theory (1866)  back 28 calculation of principal stresses in a crane, similar to orientations of trabecular bone in the proximal femur 
front 29 bone structure  back 29 bone structures are "optimized" for maximum strength with minimal weight

front 30 straightening long bones  back 30 abnormally curved long bones can straighten through remodeling

front 31 axial loads applies to long bones(bending)  back 31 axial loading on curved bone creates:

front 32 axial loads applies to long bones(gradients)  back 32 Axial loading on curved bone creates:

front 33 remodeling and repair facts  back 33 Turnover rate: ~ 5% each year

front 34 methods of bone remodeling evaluation  back 34 External bone dimensions (diameter, etc.)

front 35 The ‘Law of Bone Transformation’: A case of crying Wolff? Bertram & Swartz, 1991  back 35 testing to determine if mechanical influences can cause transformation of bone (Wolff's law)

front 36 applications of remodeling theories  back 36 Ability to predict responses to

front 37 bone remodeling feedback loops, Beaupre and carter (1990)  back 37 
front 38 daily stress stimulus equation  back 38 Daily Stress stimulus (gamma= "expected" level of stress

front 39 bone density remodeling equation  back 39 Assume linear relationship between error and apposition rate

front 40 bone remodeling procedure  back 40 Create starting model, apply loading conditions, material properties

front 41 remodeling simulations Carter (1987)  back 41 Start with arbitrary uniform modulus, then iterate until steady state

front 42 trabecular remodeling simulations Mullender (1994)  back 42 Start with arbitrary uniform modulus, then iterate until steady state

front 43 remodeling cautions  back 43 Constants needed

front 44 bone remodeling graph  back 44 
front 45 factors  back 45 variables whose influence you want to study

front 46 levels  back 46 specific values given to a factor during experiments

front 47 treatment condition  back 47 one running of the experiment

front 48 response  back 48 result measured for a treatment condition

front 49 effect  back 49 calculated from responses (y1, y2)

front 50 degrees of freedom (DOF)  back 50 counter for information

front 51 one at a time experiment (OAT)  back 51 change one factor at a time

front 52 full factorial approach  back 52 test all combinations of factors

front 53 order  back 53 number of factors in the interaction term of a factorial analysis

front 54 randomization  back 54 experiments can be influenced by time related changes (ex. temperature changes over the course of the day)

front 55 continuous factor  back 55 involves something that can be quantified on a continuous scale (ex. temperature, pressure, time, voltage, etc.) 
front 56 discrete factor  back 56 nominal, categorical

front 57 advantages and disadvantages of full factorial designs  back 57 advantages

front 58 ANalysis Of Means (ANOM)  back 58 most basic level of analysis

front 59 ANalysis Of VAriance (ANOVA)  back 59 second level of analysis

front 60 replication error  back 60 Repeat (replicate) each of the treatment conditions

front 61 error pooling of higherorder interactions  back 61 Assume that higherorder interactions are unimportant/zero

front 62 replication vs pooling  back 62 replication

front 63 anova table  back 63 typical way of presenting ANOVA results

front 64 judging statistical significance  back 64 if F>Fcritical (found from a table) or p>pcritical the factor/interaction is significant

front 65 Treatment conditions (TC)  back 65 required number of TC is the product of levels for each factor (ex. a 2 level factor and a 3 level factor need 6 TC)

front 66 why use more than 2levels?  back 66 continuous factor test nonlinear effects

front 67 fractional factorials  back 67 "fractions" of full factorials (2 level designs: 1/2 or 1/4 the # of TC)

front 68 design of fractional factorials  back 68 must preserve symmetry of design

front 69 resolution in fractional factorials  back 69 higher values indicate less severe confounding

front 70 model verification  back 70 "solving the equations right"

front 71 model validation  back 71 "solving the right equations"

front 72 validation/verification requirements for theoretical use  back 72 Requirements for numerical studies for theoretical use:

front 73 validation/verification requirements for "applied biomechanics" use  back 73 Requirements for numerical studies for "applied biomechanics" use:

front 74 validation/verification requirements for clinical use  back 74 Requirements for numerical studies for clinical use:

front 75 types of fractures  back 75 closed fracture crack/break through bones but they stay in place

front 76 what determines the type of fracture?  back 76 type of loads (tension, compression, bending, torsion)

front 77 healing process  back 77 hematoma (bringing in blood supple, bruising)

front 78 "Ilizarov type" external fracture fixation  back 78 metal external splint with wires and rods to hold the bone in place and can gradually straighten the bone with screws

front 79 things that change external fixator stiffness  back 79 screw length

front 80 intramedullary pins  back 80 insertion of a pin through the intramedullary space in the center of the bone

front 81 compression plates  back 81 Plate provides compression across transverse fracture or fragments

front 82 biomechanics of fracture healing  back 82 Interfragmentary movement

front 83 bone fatigue behavior  back 83 SN curve (left)

front 84 MinerPalmgren's Rule  back 84 combines stress states for multiple cycles of multiple types of loading

front 85 mechanisms of fractures and crack initiators in bone  back 85 loading > crack initiation (with repair prevents fatigue)> crack growth > failure
