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B. van Rietbergen

Bio: B. van Rietbergen is an academic researcher from Eindhoven University of Technology. The author has contributed to research in topics: Bone density & Bone healing. The author has an hindex of 20, co-authored 51 publications receiving 2450 citations. Previous affiliations of B. van Rietbergen include Maastricht University Medical Centre.


Papers
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Journal ArticleDOI
TL;DR: A three-dimensional digital image correlation technique is presented for strain measurements in open-cell structures such as trabecular bone and showed that a rigid translation or rotation does not affect the accuracy.

298 citations

Journal ArticleDOI
TL;DR: The present model concludes that the local stresses and strains in the articular cartilage are highly influenced by the local morphology of the collagen-fibril network, which is likely to be one of the earliest signs of OA cartilage degeneration.

293 citations

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TL;DR: A 3-D FEA model based on a hypothetical osteocyte stimulation of osteoblast bone formation, as an effect of elevated strain in the bone matrix, and a role for microcracks and disuse in promoting osteoclast resorption is presented, which provides a suitable computational framework to investigate hypothetical relationships between bone loading and metabolic expressions.

283 citations

Journal ArticleDOI
TL;DR: This work made microfinite element models of a healthy and osteoporotic human femur and found that tissue‐level strains in the osteop orotic femoral head were 70% higher on average and less uniformly distributed than those in the healthy one.
Abstract: Quantitative information about bone tissue-level loading is essential for understanding bone mechanical behavior. We made microfinite element models of a healthy and osteoporotic human femur and found that tissue-level strains in the osteoporotic femoral head were 70% higher on average and less uniformly distributed than those in the healthy one. INTRODUCTION: Bone tissue stresses and strains in healthy load-adapted trabecular architectures should be distributed rather evenly, because no bone tissue is expected to be overloaded or unused. In this study, we evaluate this paradigm with the use of microfinite element (microFE) analyses to calculate tissue-level stresses and strains for the human femur. Our objectives were to quantify the strain distribution in the healthy femur, to investigate to what extent this distribution is affected by osteoporosis, to determine if osteoporotic bone is simply bone adapted to lower load levels, and to determine the "safety factor" for trabecular bone. MATERIALS AND METHODS: microFE models of a healthy and osteoporotic proximal femur were made from microcomputed tomography images. The models consisted of over 96 and 71 million elements for the healthy and osteoporotic femur, respectively, and represented their internal and external morphology in detail. Stresses and strains were calculated for each element and their distributions were calculated for a volume of interest (VOI) of trabecular bone in the femoral head. RESULTS: The average tissue-level principal strain magnitude in the healthy VOI was 304 +/- 185 microstrains and that in the osteoporotic VOI was 520 +/- 355 microstrains. Calculated safety factors were 8.6 for the healthy and 4.9 for the osteoporotic femurs. After reducing the force applied to the osteoporotic model to 59%, the average strain compared with that of the healthy femur, but the SD was larger (208 microstrains). CONCLUSIONS: Strain magnitudes in the osteoporotic bone were much higher and less uniformly distributed than those in the healthy one. After simulated joint-load reduction, strain magnitudes in the osteoporotic femur were very similar to those in the healthy one, but their distribution is still wider and thus less favorable.

218 citations

Journal ArticleDOI
01 Jan 2008-Bone
TL;DR: It was concluded that the osteoporotic femur was not 'over-adapted' to habitual loads, and Distributions of maximal principal strain and effective strain in the entire model suggest that the contributions to bone strength of the trabecular and cortical structures are similar.

174 citations


Cited by
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Journal ArticleDOI
TL;DR: Standard nomenclature, outlined in this article, should be followed for reporting of results of µCT‐derived bone morphometry and density measurements.
Abstract: Use of high-resolution micro-computed tomography (microCT) imaging to assess trabecular and cortical bone morphology has grown immensely. There are several commercially available microCT systems, each with different approaches to image acquisition, evaluation, and reporting of outcomes. This lack of consistency makes it difficult to interpret reported results and to compare findings across different studies. This article addresses this critical need for standardized terminology and consistent reporting of parameters related to image acquisition and analysis, and key outcome assessments, particularly with respect to ex vivo analysis of rodent specimens. Thus the guidelines herein provide recommendations regarding (1) standardized terminology and units, (2) information to be included in describing the methods for a given experiment, and (3) a minimal set of outcome variables that should be reported. Whereas the specific research objective will determine the experimental design, these guidelines are intended to ensure accurate and consistent reporting of microCT-derived bone morphometry and density measurements. In particular, the methods section for papers that present microCT-based outcomes must include details of the following scan aspects: (1) image acquisition, including the scanning medium, X-ray tube potential, and voxel size, as well as clear descriptions of the size and location of the volume of interest and the method used to delineate trabecular and cortical bone regions, and (2) image processing, including the algorithms used for image filtration and the approach used for image segmentation. Morphometric analyses should be based on 3D algorithms that do not rely on assumptions about the underlying structure whenever possible. When reporting microCT results, the minimal set of variables that should be used to describe trabecular bone morphometry includes bone volume fraction and trabecular number, thickness, and separation. The minimal set of variables that should be used to describe cortical bone morphometry includes total cross-sectional area, cortical bone area, cortical bone area fraction, and cortical thickness. Other variables also may be appropriate depending on the research question and technical quality of the scan. Standard nomenclature, outlined in this article, should be followed for reporting of results.

3,298 citations

Journal ArticleDOI
TL;DR: In this paper, the basic principles involved in designing hierarchical biological materials, such as cellular and composite architectures, adapative growth and as well as remodeling, are discussed, and examples that are found to utilize these strategies include wood, bone, tendon, and glass sponges.

2,274 citations

Journal ArticleDOI
TL;DR: Preclinical results establish sclerostin's role as a pivotal negative regulator of bone formation in the aging skeleton and suggest that antibody‐mediated inhibition of sclerOSTin represents a promising new therapeutic approach for the anabolic treatment of bone‐related disorders, such as postmenopausal osteoporosis.
Abstract: The development of bone-rebuilding anabolic agents for potential use in the treatment of bone loss conditions, such as osteoporosis, has been a long-standing goal. Genetic studies in humans and mice have shown that the secreted protein sclerostin is a key negative regulator of bone formation, although the magnitude and extent of sclerostin's role in the control of bone formation in the aging skeleton is still unclear. To study this unexplored area of sclerostin biology and to assess the pharmacologic effects of sclerostin inhibition, we used a cell culture model of bone formation to identify a sclerostin neutralizing monoclonal antibody (Scl-AbII) for testing in an aged ovariectomized rat model of postmenopausal osteoporosis. Six-month-old female rats were ovariectomized and left untreated for 1 yr to allow for significant estrogen deficiency-induced bone loss, at which point Scl-AbII was administered for 5 wk. Scl-AbII treatment in these animals had robust anabolic effects, with marked increases in bone formation on trabecular, periosteal, endocortical, and intracortical surfaces. This not only resulted in complete reversal, at several skeletal sites, of the 1 yr of estrogen deficiency-induced bone loss, but also further increased bone mass and bone strength to levels greater than those found in non-ovariectomized control rats. Taken together, these preclinical results establish sclerostin's role as a pivotal negative regulator of bone formation in the aging skeleton and, furthermore, suggest that antibody-mediated inhibition of sclerostin represents a promising new therapeutic approach for the anabolic treatment of bone-related disorders, such as postmenopausal osteoporosis.

750 citations

Journal ArticleDOI
TL;DR: Deterioration in vertebral and femoral trabecular microarchitecture begins early, continues throughout life, is more pronounced at the femoral metaphysis than in the vertebrae, and is greater in females than males.
Abstract: We used μCT and histomorphometry to assess age-related changes in bone architecture in male and female C57BL/6J mice. Deterioration in vertebral and femoral trabecular microarchitecture begins early, continues throughout life, is more pronounced at the femoral metaphysis than in the vertebrae, and is greater in females than males. Introduction: Despite widespread use of mice in the study of musculoskeletal disease, the age-related changes in murine bone structure and the relationship to whole body BMD changes are not well characterized. Thus, we assessed age-related changes in body composition, whole body BMD, and trabecular and cortical microarchitecture at axial and appendicular sites in mice. Materials and Methods: Peripheral DXA was used to assess body composition and whole body BMD in vivo, and μCT and histomorphometry were used to measure trabecular and cortical architecture in excised femora, tibia, and vertebrae in male and female C57BL/6J mice at eight time-points between 1 and 20 mo of age (n = 6–9/group). Results: Body weight and total body BMD increased with age in male and female, with a marked increase in body fat between 6 and 12 mo of age. In contrast, trabecular bone volume (BV/TV) was greatest at 6–8 wk of age and declined steadily thereafter, particularly in the metaphyseal region of long bones. Age-related declines in BV/TV were greater in female than male. Trabecular bone loss was characterized by a rapid decrease in trabecular number between 2 and 6 mo of age, and a more gradual decline thereafter, whereas trabecular thickness increased slowly over life. Cortical thickness increased markedly from 1 to 3 mo of age and was maintained or slightly decreased thereafter. Conclusions: In C57BL/6J mice, despite increasing body weight and total body BMD, age-related declines in vertebral and distal femoral trabecular bone volume occur early and continue throughout life and are more pronounced in females than males. Awareness of these age-related changed in bone morphology are critical for interpreting the skeletal response to pharmacologic interventions or genetic manipulation in mice.

520 citations

Journal ArticleDOI
TL;DR: In this paper, the onset and evolution of localised deformation processes in sand with grain-scale resolution was observed and quantified by combining state-of-the-art X-ray micro tomography imaging with 3D volumetric digital image correlation techniques.
Abstract: The objective of this work was to observe and quantify the onset and evolution of localised deformation processes in sand with grain-scale resolution. The key element of the proposed approach is combining state-of-the-art X-ray micro tomography imaging with three-dimensional volumetric digital image correlation techniques. This allows not only the grain-scale details of a deforming sand specimen to be viewed, but also, and more importantly, the evolving three-dimensional displacement and strain fields throughout loading to be assessed. X-ray imaging and digital image correlation have been in the past applied individually to study sand deformation, but the combination of these two methods to study the kinematics of shear band formation at the grain scale is the first novel aspect of this work. Moreover, the authors have developed a completely original grain-scale volumetric digital image correlation method that permits the characterisation of the full kinematics (i.e. three-dimensional displacements and rotations) of all the individual sand grains in a specimen. The results obtained using the discrete volumetric digital image correlation confirm the importance of grain rotations associated with strain localisation.

503 citations