Application of Neural Network and Finite Element Method for Multiscale Prediction of Bone Fatigue Crack Growth in Cancellous Bone - Multiscale Computer Modeling in Biomechanics and Biomedical Engineering - page 11

Table 1 Distribution and microarchitectural information of specimens by anatomic site, FN
femoral neck, GT greater trochanter
Training/
validation

Apparent Young's
modulus (MPa)
T 64 GT 12.612 1.41361 0.178 404
V 88 FN 15.560 1.18315 0.296 694
T 92 GT 16.956 1.25774 0.322 867
T 74 FN 17.420 0.89504 0.331 929
T 84 GT 17.620 0.69379 0.335 957
V 89 GT 17.715 0.54028 0.337 970
T 92 FN 18.225 0.89345 0.346 1044
T 91 FN 18.532 1.03561 0.352 1090
T 86 FN 18.562 1.0013 0.353 1095
V 94 GT 19.330 1.05269 0.367 1215
T 95 GT 20.348 0.90966 0.387 1387
T 84 FN 23.048 0.8242 0.438 1913
T 98 GT 23.682 0.42063 0.450 2052
V 82 FN 25.035 0.95246 0.476 2368
T 90 GT 26.200 0.78813 0.498 2663
T 68 GT 27.266 0.90167 0.518 2952
V 84 GT 28.988 0.97644 0.551 3457
T 50 GT 30.410 0.56246 0.578 3912
T 51 FN 31.019 0.44852 0.589 4117
V 61 FN 33.330 0.32045 0.633 4956
T 86 FN 34.232 0.22346 0.650 5309
V - FN 39.482 0.15987 0.750 7672
T 88 FN 56.347 0.09023 1.071 13206
Fifteen specimens were used for training (T) and eight specimens were kept for validation (V).
SMI structure model index

Age Anatomic

site

BV = TV
(%)

SMI Ash density

(g/cm 3 )

20 lm (microarchitectural information is given in Table 1 ). Some representative
images from different anatomic sites are shown in Fig. 6 .
The digital image-based modeling technique using micro-CT (Skyscan 1072
system) and voxel FE at 20 lm voxel sizes were used to simulate the fatigue
behaviour of the trabecular samples under varying cyclic compressive stresses.
Despite the small size of the bone samples, the model satisfied the continuum
assumption for trabecular bone (i.e. at least five intertrabecular lengths in size) [ 24 ].

3.3 Factors Affecting the Fatigue Damage Accumulation in Bone

Several factors can affect the evolution of Cr.Dn and Cr.Le within trabecular bone.
These factors include the trabecular bone architectural parameters (BV = TV , SMI,
porosity, Tb.N, Tb.Sp, Tb.Th, …), bone material parameters (elastic modulus,