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  • 1
    In: Journal of Bone and Mineral Research, Oxford University Press (OUP), ( 2024-06-18)
    Abstract: Knee osteoarthritis (OA), characterized by multiple joint tissue degenerations, remains a significant clinical challenge. Recent evidence suggests that crosstalk within the osteochondral unit may drive OA progression. While structural-biomechanical properties of bone and cartilage have been studied, potential interaction within the osteochondral unit in the context of OA has yet to be investigated. We performed comprehensive structural and biomechanical quantification of the cartilage, subchondral bone plate, and subchondral trabecular bone using 101 osteochondral cores collected from tibial plateaus of 12 control human cadavers (CT, 5 male/7 female) and 19 patients undergoing total knee replacement (OA, 6 male/13 female). For each sample, we quantified subchondral bone plate microstructure, plate-and-rod morphological properties of the subchondral trabecular bone using individual trabecula segmentation, and morphological and compositional properties of the articular cartilage. We also performed indentation testing on each compartment of the osteochondral unit to extract the respective structural-mechanical properties. Cartilage thickness was lower in moderate and severe OA regions, while OARSI score was higher only in severe OA regions. GAG content did not change in any OA region. Aggregate and shear moduli were lower only in severe OA regions, while permeability was lower only in moderate OA regions. In the subchondral bone plate, thickness and TMD were higher in moderate and severe OA regions. Tissue modulus of subchondral trabecular bone was lower in moderate OA regions despite a thicker and more mineralized subchondral bone plate; this deterioration was not observed in severe OA regions. Regression analysis revealed strong correlations between cartilage and subchondral trabecular bone properties in CT; these correlations were also found in moderate OA regions but were not observed in severe OA regions. In summary, our findings comprehensively characterize the human OA osteochondral unit. Importantly, uncoupling cartilage and subchondral bone structural-mechanical properties may be a hallmark of OA.
    Type of Medium: Online Resource
    ISSN: 0884-0431 , 1523-4681
    RVK:
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2024
    detail.hit.zdb_id: 2008867-X
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  • 2
    In: Journal of Biomechanical Engineering, ASME International, Vol. 141, No. 9 ( 2019-09-01)
    Abstract: High-resolution peripheral quantitative computed tomography (HR-pQCT) is a promising imaging modality that provides an in vivo three-dimensional (3D) assessment of bone microstructure by scanning fixed regions of the distal radius and tibia. However, how microstructural parameters and mechanical analysis based on these segment scans correlate to whole distal radius and tibia mechanics are not well-characterized. On 26 sets of cadaveric radius and tibia, HR-pQCT scans were performed on the standard scan segment, a segment distal to the standard segment, and a segment proximal to the standard segment. Whole distal radius and tibia stiffness were determined through mechanical testing. Segment bone stiffness was estimated using linear finite element (FE) analysis based on segment scans. Standard morphological and individual trabecula segmentation (ITS) analyses were used to estimate microstructural properties. Significant variations in microstructural parameters were observed among segments at both sites. Correlation to whole distal radius and tibia stiffness was moderate for microstructural parameters at the standard segment, but correlation was significantly increased for FE-predicted segment bone stiffness based on standard segment scans. Similar correlation strengths were found between FE-predicted segment bone stiffness and whole distal radius and tibia stiffness. Additionally, microstructural parameters at the distal segment had higher correlation to whole distal radius and tibia stiffness than at standard or proximal segments. Our results suggest that FE-predicted segment stiffness is a better predictor of whole distal radius and tibia stiffness for clinical HR-pQCT analysis and that microstructural parameters at the distal segment are more highly correlated with whole distal radius and tibia stiffness than at the standard or proximal segments.
    Type of Medium: Online Resource
    ISSN: 0148-0731 , 1528-8951
    Language: English
    Publisher: ASME International
    Publication Date: 2019
    SSG: 31
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  • 3
    In: Journal of Bone and Mineral Research, Wiley, Vol. 36, No. 9 ( 2021-09), p. 1796-1807
    Abstract: Trabecular plates and rods determine apparent elastic modulus and yield strength of trabecular bone, serving as important indicators of bone's mechanical integrity in health and disease. Although trabecular bone's apparent‐level mechanical properties have been widely reported, tissue mechanical properties of individual trabeculae have not been fully characterized. We systematically measured tissue mineral density (TMD)–dependent elastic modulus of individual trabeculae using microindentation and characterized its anisotropy as a function of trabecular type (plate or rod), trabecular orientation in the global coordinate (longitudinal, oblique, or transverse along the anatomic loading axis), and indentation direction along the local trabecular coordinate (axial or lateral). Human trabecular bone samples were scanned by micro‐computed tomography for TMD and microstructural measurements. Individual trabecula segmentation was used to decompose trabecular network into individual trabeculae, where trabecular type and orientation were determined. We performed precise, selective indentation of trabeculae in each category using a custom‐built, microscope‐coupled microindentation device. Co‐localization of TMD at each indentation site was performed to obtain TMD‐to‐modulus correlations. We found significantly higher TMD and tissue modulus in trabecular plates than rods. Regardless of trabecular type and orientation, axial tissue modulus was consistently higher than lateral tissue modulus, with ratios ranging from 1.13 to 1.41. Correlations between TMD and tissue modulus measured from axial and lateral indentations were strong but distinct: axial correlation predicted higher tissue modulus than lateral correlation at the same TMD level. To assess the contribution of experimentally measured anisotropic tissue properties of individual trabeculae to apparent‐level mechanics, we constructed non‐linear micro‐finite element models using a new set of trabecular bone samples and compared model predictions to mechanical testing measurements. Heterogeneous anisotropic models accurately predicted apparent elastic modulus but were no better than a simple homogeneous isotropic model. Variances in tissue‐level properties may therefore contribute nominally to apparent‐level mechanics in normal human trabecular bone. © 2021 American Society for Bone and Mineral Research (ASBMR).
    Type of Medium: Online Resource
    ISSN: 0884-0431 , 1523-4681
    URL: Issue
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    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2008867-X
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  • 4
    In: Science Advances, American Association for the Advancement of Science (AAAS), Vol. 7, No. 48 ( 2021-11-26)
    Abstract: Architectured materials offer tailored mechanical properties but are limited in engineering applications due to challenges in maintaining toughness across their attachments. The enthesis connects tendon and bone, two vastly different architectured materials, and exhibits toughness across a wide range of loadings. Understanding the mechanisms by which this is achieved could inform the development of engineered attachments. Integrating experiments, simulations, and previously unexplored imaging that enabled simultaneous observation of mineralized and unmineralized tissues, we identified putative mechanisms of enthesis toughening in a mouse model and then manipulated these mechanisms via in vivo control of mineralization and architecture. Imaging uncovered a fibrous architecture within the enthesis that controls trade-offs between strength and toughness. In vivo models of pathology revealed architectural adaptations that optimize these trade-offs through cross-scale mechanisms including nanoscale protein denaturation, milliscale load-sharing, and macroscale energy absorption. Results suggest strategies for optimizing architecture for tough bimaterial attachments in medicine and engineering.
    Type of Medium: Online Resource
    ISSN: 2375-2548
    Language: English
    Publisher: American Association for the Advancement of Science (AAAS)
    Publication Date: 2021
    detail.hit.zdb_id: 2810933-8
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  • 5
    In: Bone, Elsevier BV, Vol. 154 ( 2022-01), p. 116187-
    Type of Medium: Online Resource
    ISSN: 8756-3282
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2022
    detail.hit.zdb_id: 1496324-3
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  • 6
    In: Bone, Elsevier BV, Vol. 167 ( 2023-02), p. 116638-
    Type of Medium: Online Resource
    ISSN: 8756-3282
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2023
    detail.hit.zdb_id: 1496324-3
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  • 7
    In: JBMR Plus, Oxford University Press (OUP)
    Abstract: High-resolution peripheral quantitative computed tomography (HR-pQCT) has been used for in vivo 3D visualization of trabecular microstructure. Second-generation HR-pQCT (HR-pQCT II) has been shown to have good agreement with first generation HR-pQCT (HR-pQCT I). Advanced Individual Trabecula Segmentation (ITS) decomposes the trabecula network into individual plates and rods. ITS based on HR-pQCT I showed a strong correlation to ITS based on micro-computed tomography (μCT) and identified trabecular changes in metabolic bone diseases. ITS based on HR-pQCT II has new potential because of the enhanced resolution but has yet to be validated. The objective of this study was to assess the agreement between ITS based on HR-pQCT I, HR-pQCT II, and μCT to assess the capability of ITS on HR-pQCT images as a tool for studying bone structure. Freshly frozen tibia and radius bones were scanned in the distal region using HR-pQCT I at 82 μm, HR-pQCT II at 60.7 μm and μCT at 37 μm. Images were registered, binarized and ITS analysis was performed. Bone volume fraction (pBV/TV, rBV/TV), number density (pTb.N, rTb.N), thickness (pTb.Th, rTb.Th) and plate-to-rod (PR) ratio (pBV/rBV) of trabecular plates and rods were obtained. Paired Student’s t-tests with post-hoc Bonferroni analysis were used to examine the differences. Linear regression was used to determine the correlation coefficient. The HR-pQCT I parameters were different from the μCT measurements. The HR-pQCT II parameters were different from the μCT measurements except for rTb.N and the HR-pQCT I parameters were different from the HR-pQCT II measurements except for pTb.Th. The strong correlation between HR-pQCT II and μCT microstructural analysis (R2 =0.55-0.94) suggests that HR-pQCT II can be used to assess changes in plate and rod microstructure and that values from HR-pQCT I can be corrected.
    Type of Medium: Online Resource
    ISSN: 2473-4039
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2024
    detail.hit.zdb_id: 2905710-3
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  • 8
    In: Journal of Biomechanical Engineering, ASME International, Vol. 141, No. 4 ( 2019-04-01)
    Abstract: The high-resolution peripheral quantitative computed tomography (HR-pQCT) provides unprecedented visualization of bone microstructure and the basis for constructing patient-specific microfinite element (μFE) models. Based on HR-pQCT images, we have developed a plate-and-rod μFE (PR μFE) method for whole bone segments using individual trabecula segmentation (ITS) and an adaptive cortical meshing technique. In contrast to the conventional voxel approach, the complex microarchitecture of the trabecular compartment is simplified into shell and beam elements based on the trabecular plate-and-rod configuration. In comparison to voxel-based μFE models of μCT and measurements from mechanical testing, the computational and experimental gold standards, nonlinear analyses of stiffness and yield strength using the HR-pQCT-based PR μFE models demonstrated high correlation and accuracy. These results indicated that the combination of segmented trabecular plate-rod morphology and adjusted cortical mesh adequately captures mechanics of the whole bone segment. Meanwhile, the PR μFE modeling approach reduced model size by nearly 300-fold and shortened computation time for nonlinear analysis from days to within hours, permitting broader clinical application of HR-pQCT-based nonlinear μFE modeling. Furthermore, the presented approach was tested using a subset of radius and tibia HR-pQCT scans of patients with prior vertebral fracture in a previously published study. Results indicated that yield strength for radius and tibia whole bone segments predicted by the PR μFE model was effective in discriminating vertebral fracture subjects from nonfractured controls. In conclusion, the PR μFE model of HR-pQCT images accurately predicted mechanics for whole bone segments and can serve as a valuable clinical tool to evaluate musculoskeletal diseases.
    Type of Medium: Online Resource
    ISSN: 0148-0731 , 1528-8951
    Language: English
    Publisher: ASME International
    Publication Date: 2019
    SSG: 31
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