scholarly journals Short-Term Bone Formation is Greatest Within High Strain Regions of the Human Distal Radius: A Prospective Pilot Study

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Varun A. Bhatia ◽  
W. Brent Edwards ◽  
Joshua E. Johnson ◽  
Karen L. Troy
Keyword(s):  
Distal Radius ◽  
Bone Mineral ◽  
Local Level ◽  
Equivalent Strain ◽  
Bone Adaptation ◽  
Mechanical Stimuli ◽  
Mineral Density ◽  
Energy Equivalent ◽  
Strain Adaptation

Bone adaptation is understood to be driven by mechanical strains acting on the bone as a result of some mechanical stimuli. Although the strain/adaptation relation has been extensively researched using in vivo animal loading models, it has not been studied in humans, likely due to difficulties in quantifying bone strains and adaptation in living humans. Our purpose was to examine the relationship between bone strain and changes in bone mineral parameters at the local level. Serial computed tomography (CT) scans were used to calculate 14 week changes in bone mineral parameters at the distal radius for 23 women participating in a cyclic in vivo loading protocol (leaning onto the palm of the hand), and 12 women acting as controls. Strains were calculated at the distal radius during the task using validated finite element (FE) modeling techniques. Twelve subregions of interest were selected and analyzed to test the strain/adaptation relation at the local level. A positive relationship between mean energy equivalent strain and percent change in bone mineral density (BMD) (slope = 0.96%/1000 με, p < 0.05) was observed within experimental, but not control subjects. When subregion strains were grouped by quartile, significant slopes for quartile versus bone mineral content (BMC) (0.24%/quartile) and BMD (0.28%/quartile) were observed. Increases in BMC and BMD were greatest in the highest-strain quartile (energy equivalent strain > 539 με). The data demonstrate preliminary prospective evidence of a local strain/adaptation relationship within human bone. These methods are a first step toward facilitating the development of personalized exercise prescriptions for maintaining and improving bone health.

scholarly journals Sost deficiency leads to reduced mechanical strains at the tibia midshaft in strain-matched in vivo loading experiments in mice

2018 ◽  
Vol 15 (141) ◽  
pp. 20180012 ◽  
Author(s):  
Laia Albiol ◽  
Myriam Cilla ◽  
David Pflanz ◽  
Ina Kramer ◽  
Michaela Kneissel ◽  
...  
Keyword(s):  
Bone Formation ◽  
Cortical Bone ◽  
Neutralizing Antibodies ◽  
Bone Geometry ◽  
Bone Adaptation ◽  
Mechanical Stimuli ◽  
Mineral Density ◽  
Littermate Control ◽  
Mechanical Environment

Sclerostin, a product of the Sost gene, is a Wnt-inhibitor and thus negatively regulates bone accrual. Canonical Wnt/β-catenin signalling is also known to be activated in mechanotransduction. Sclerostin neutralizing antibodies are being tested in ongoing clinical trials to target osteoporosis and osteogenesis imperfecta but their interaction with mechanical stimuli on bone formation remains unclear. Sost knockout (KO) mice were examined to gain insight into how long-term Sost deficiency alters the local mechanical environment within the bone. This knowledge is crucial as the strain environment regulates bone adaptation. We characterized the bone geometry at the tibial midshaft of young and adult Sost KO and age-matched littermate control (LC) mice using microcomputed tomography imaging. The cortical area and the minimal and maximal moment of inertia were higher in Sost KO than in LC mice, whereas no difference was detected in either the anterior–posterior or medio-lateral bone curvature. Differences observed between age-matched genotypes were greater in adult mice. We analysed the local mechanical environment in the bone using finite-element models (FEMs), which showed that strains in the tibiae of Sost KO mice are lower than in age-matched LC mice at the diaphyseal midshaft, a region commonly used to assess cortical bone formation and resorption. Our FEMs also suggested that tissue mineral density is only a minor contributor to the strain distribution in tibial cortical bone from Sost KO mice compared to bone geometry. Furthermore, they indicated that although strain gauging experiments matched strains at the gauge site, strains along the tibial length were not comparable between age-matched Sost KO and LC mice or between young and adult animals within the same genotype.

scholarly journals Physical activity and bone: The importance of the various mechanical stimuli for bone mineral density. A review

2011 ◽  
Vol 20 (2) ◽  
Author(s):  
Bente Morseth ◽  
Nina Emaus ◽  
Lone Jørgensen
Keyword(s):  
Physical Activity ◽  
Bone Mineral Density ◽  
Bone Mineral ◽  
Bone Adaptation ◽  
Mechanical Stimuli ◽  
Mineral Density ◽  
Cross Sectional ◽  
Gravitational Forces ◽  
Joint Forces ◽  
Reaction Forces

Numerous studies have reported benefits of regular physical activity on bone mineral density (BMD). The effects of physical activity on BMD are primarily linked to the mechanisms of mechanical loading, but the understanding of the precise mechanism behind the association is incomplete. The aim of this paper was to review the main findings concerning sources and types of mechanical stimuli in relation to BMD. Mechanical forces that act on bone are generated from impact with the ground (ground-reaction forces) and from skeletal muscle contractions (muscle forces or muscle-joint forces), but the relative importance of these two sources has not been elucidated. Both muscle-joint forces and gravitational forces seem to be able to induce bone adaptation independently, and there may be differences in the importance of loading sources at different skeletal sites. The nature of the stimuli is affected by the type, intensity, frequency, and duration of the activity. The activity should be dynamic, not static, and the magnitude and rate of the stimuli should be high. In accordance with this, cross-sectional studies report highest BMD in athletes of high-impact activities such as dancing, soccer, volleyball, basketball, squash, speed skating, gymnastics, hockey, and step-aerobics. Endurance activities such as orienteering, skiing, and triathlon seem to be beneficial to a lesser degree, whereas low-impact activities such as swimming and cycling are associated with lower BMD than controls. Both the intensity and frequency of the activity should be varied and increased beyond the habitual level. Duration of the activity seems to be less important, and a few loading cycles seem to be sufficient.

Ischemic heart disease is associated with lower cortical volumetric bone mineral density of distal radius

2015 ◽  
Vol 26 (7) ◽  
pp. 1893-1901 ◽  
Author(s):  
J. Paccou ◽  
M. H. Edwards ◽  
K. A. Ward ◽  
K. A. Jameson ◽  
C. L. Moss ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Heart Disease ◽  
Ischemic Heart Disease ◽  
Distal Radius ◽  
Bone Mineral ◽  
Ischemic Heart ◽  
Volumetric Bone Mineral Density ◽  
Mineral Density

The effects of ovariectomy on bone mineral density, geometrical, and biomechanical characteristics in the rabbit femur

2010 ◽  
Vol 23 (01) ◽  
pp. 31-36 ◽  
Author(s):  
M. E. Kara ◽  
F. Sevil
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Animal Studies ◽  
Biomechanical Properties ◽  
Mineral Density ◽  
Cross Sectional ◽  
Tomographic Images ◽  
Three Point Bending ◽  
Rabbit Femur

SummaryThe aim of the study was to evaluate the bone mineral density, as well as the biomechanic and morphometric changes in the femur of ovariectomised rabbits.Twenty-four six-month-old New Zealand rabbits were randomly divided into an ovariectomy (n = 12) and a sham (n = 12) group. Six rabbits in each group were euthanatized at eight and 16 weeks after surgery, and the femora were resected. The morphometric data were obtained from tomographic images. Periosteal and endosteal diameters and cortical thickness were measured. Total cross-sectional, cortical and medullary areas were also measured. The bone mineral content, the bone area and the bone mineral density were measured from the proximal, distal and mid-shaft of the femur as well as the total femur by dual energy X-ray absorptiometry. Employing the three-point bending method, the ultimate force, stiffness and work-to-failure were measured. The mechanical data were normalised to obtain intrinsic biomechanical properties such as ultimate stress, elastic modulus, and toughness, all of which are independent of size and shape.The results indicated that the femur was both larger and weaker 16 weeks after surgery in the ovariectomised group. Results also suggest that the rabbit might be a useful animal model for investigation of diseases related to oestrogen loss such as human postmenopausal osteoporosis. However, additional studies with advanced techniques at several time points via in vivo animal studies, and precision and predictability analyses should be designed to standardise the rabbit as a model for osteoporosis.

scholarly journals DETERMINATION OF BONE MINERAL DENSITY AT DISTAL RADIUS MEASURED BY SINGLE PHOTON ABSORPTIOMETRY : NEW INDEX FOR BONE MINERAL DENSITY

1988 ◽  
Vol 44 (7) ◽  
pp. 745-749
Author(s):  
TATSUSHI TOMOMITSU ◽  
SHINICHI YANAGIMOTO ◽  
GO HITOMI ◽  
AKIHIKO MURAKAMI ◽  
SHINJI SUEMORI ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Distal Radius ◽  
Bone Mineral ◽  
Single Photon ◽  
Mineral Density ◽  
Single Photon Absorptiometry ◽  
Photon Absorptiometry

scholarly journals Assessing bone mineral density in vivo: digitized fluoroscopy and ultrasound

2004 ◽  
Vol 83 (2) ◽  
pp. 207-214 ◽  
Author(s):  
R.H. Fleming ◽  
D. Korver ◽  
H.A. McCormack ◽  
C.C. Whitehead
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Mineral Density
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