Although microdamage is known to accumulate in trabecular bone with overloading and aging, the tissue-level stresses and strains associated with local bone failure are not well known. Local correlation of microdamage with microstructural stresses and strains requires methods to accurately register histological sections with micro-computed tomography (micro-CT) based finite element models. In addition, the resolution of correlation (i.e., grid size) selected for analysis may affect the observed results. Therefore, an automated, repeatable, and accurate image registration algorithm was developed to determine the range of local stresses and strains associated with microdamage initiation. Using a two-dimensional rigid registration algorithm, bone structures from histology and micro-CT imaging were aligned. Once aligned, microdamaged regions were spatially correlated with local stresses and strains obtained from micro-CT based finite element analysis. Using this more sophisticated registration technique, we were able to analyze the effects of varying spatial grid resolution on local stresses and strains initiating microdamage. The results indicated that grid refinement to the individual pixel level (pixel-by-pixel method) more precisely defined the range of microdamage initiation compared to manually selected individual damaged and undamaged trabeculae. Using the pixel-by-pixel method, we confirmed that trabecular bone from younger cows sustained higher local strains prior to microdamage initiation compared to older bone.

References

1.
AAOS. Osteoporosis and Bone Health
. In:
Burden of Musculoskeletal Diseases in the United States: Prevalence, Societal and Economic Cost
. 1st ed:
American Academy of Orthopaedic Surgeons
; 2008, pp.
97
121
.
2.
Keaveny
,
T. M.
,
Morgan
,
E. F.
,
Niebur
,
G. I.
, and
Yeh
,
O. C.
, 2001, “
Biomechanics of Trabecular Bone
,”
Annu. Rev. Biomed. Eng.
,
3
, pp.
307
333
.
3.
Van Rietbergen
,
B.
,
Weinans
,
H.
, and
Huiskes
,
R.
, 1996, “
Computational Strategies for Iterative Solutions of Large FEM Applications Employing Voxel Data
,”
Int. J. Numer. Methods Eng.
,
39
, pp.
2743
2767
.
4.
Lee
,
T. C.
,
Mohsin
,
S.
,
Taylor
,
D.
,
Parkesh
,
R.
,
Gunnlaugsson
,
T.
,
O’Brien
,
F. J.
,
Giehl
,
M.
, and
Gowin
,
W.
, 2003, “
Detecting Microdamage in Bone
,”
J. Anat.
,
203
, pp.
161
172
.
5.
Lynch
,
J. A.
,
Grigoryan
,
M.
,
Fierlinger
,
A.
,
Guermazi
,
A.
,
Zaim
,
S.
,
MacLean
,
D. B.
, and
Genant
,
H. K.
, 2004, “
Measurement of Changes in Trabecular Bone at Fracture Sites Using X-Ray CT and Automated Image Registration and Processing
,”
J. Orthop. Res.
,
22
, pp.
362
367
.
6.
Newitt
,
D. C.
,
van Rietbergen
,
B.
, and
Majumdar
,
S.
, 2002, “
Processing and Analysis of In Vivo High-Resolution MR Images of Trabecular Bone for Longitudinal Studies: Reproducibility of Structural Measures and Micro-Finite Element Analysis Derived Mechanical Properties
,”
Osteoporosis Int.
,
13
, pp.
278
287
.
7.
Waarsing
,
J. H.
,
Day
,
J. S.
,
van der Linden
,
J. C.
,
Ederveen
,
A. G.
,
Spanjers
,
C.
,
De Clerck
,
N.
,
Sasov
,
A.
,
Verhaar
,
J. A.
, and
Weinans
,
H.
, 2004, “
Detecting and Tracking Local Changes in the Tibiae of Individual Rats: A Novel Method to Analyse Longitudinal In Vivo Micro-CT Data
,”
Bone
,
34
, pp.
163
169
.
8.
Nagaraja
,
S.
,
Lin
,
A. S.
, and
Guldberg
,
R. E.
, 2007, “
Age-Related Changes in Trabecular Bone Microdamage Initiation
,”
Bone
,
40
, pp.
973
980
.
9.
Keaveny
,
T. M.
,
Wachtel
,
E. F.
,
Ford
,
C. M.
, and
Hayes
,
W. C.
, 1994, “
Differences Between the Tensile and Compressive Strengths of Bovine Tibial Trabecular Bone Depend on Modulus
,”
J. Biomech.
,
27
, pp.
1137
1146
.
10.
Lee
,
T. C.
,
Arthur
,
T. L.
,
Gibson
,
L. J.
, and
Hayes
,
W. C.
, 2000, “
Sequential Labelling of Microdamage in Bone Using Chelating Agents
,”
J. Orthop. Res.
,
18
, pp.
322
325
.
11.
O’Brien
,
F. J.
,
Taylor
,
D.
, and
Lee
,
T. C.
, 2002, “
An Improved Labelling Technique for Monitoring Microcrack Growth in Compact Bone
,”
J. Biomech.
,
35
, pp.
523
526
.
12.
Van Rietbergen
,
B.
,
Weinans
,
H.
,
Huiskes
,
R.
, and
A.
Odgaard
, A., 1995, “
A New Method to Determine Trabecular Bone Elastic Properties and Loading Using Micromechanical Finite-Element Models
,”
J. Biomech.
,
28
, pp.
69
81
.
13.
McNamara
,
L. M.
,
Van der Linden
,
J. C.
,
Weinans
,
H.
, and
Prendergast
,
P. J.
, 2006, “
Stress-Concentrating Effect of Resorption Lacunae in Trabecular Bone
,”
J. Biomech.
,
39
, pp.
734
741
.
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