Characterization of in vivo strain in the rat tibia during external application of a four-point bending load

Akhter, Mohammed P.; Raab, Diane M.; Turner, Charles H.; Kimmel, Donald B.; Recker, Robert R.

doi:10.1016/0021-9290(92)90082-c

Cited by 85 publications

(44 citation statements)

References 15 publications

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“…It is well accepted that bone mass and bone density are not the sole determinants of ultimate bone strength,and a great contribution is also provided by tissue and geometric properties. (20,21) The latter are generally not considered in the routine clinical assessment of osteoporosis for technical, cultural,and practical problems. In the clinical ground nowadays,the only technology that can provide in vivo geometric insights is computed tomography, yet the correlation between a given shape of cortical bone and its resistance to a clinically relevant bending strain is poorly defined.…”

Section: Discussionmentioning

confidence: 99%

Site-Specific Effects of Strength Training on Bone Structure and Geometry of Ultradistal Radius in Postmenopausal Women

Адами

Gatti

Braga

et al. 1999

Journal of Bone and Mineral Research

146

129

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Knowledge of the effects of exercise on bone mass in postmenopausal women is limited and controversial. Animal studies have shown that the response of bone to bending strain is an alteration of bone geometry. We studied 250 postmenopausal women, aged 52-72 years, willing to participate in a 6-month exercise program. The first 125 started the program immediately and the remaining 125 served as controls. The training program included exercises designed to maximize the stress on the wrist. One hundred and eighteen of the active group and 116 of the control group completed the study and were reassessed 6 months later. Bone mineral density (BMD) of the femoral neck, lumbar spine, ultradistal and proximal radius was measured by dual-energy X-ray absorptiometry (DXA) both before and at the end of the exercise program. The forearm was also evaluated by peripheral quantitative computed tomography, which measures the area, bone mineral content (BMC), and volumetric density for both the cortical and the trabecular component. The results showed that the DXA measurements at the femoral neck, lumbar spine, ultradistal and proximal radius were similar between the two groups. No significant difference was detected after the exercise program at the proximal radius. At the ultradistal radius, the crosssectional area of cortical bone rose by 2.8 ± 15.0% (SD, p < 0.05), apparently for both periosteal apposition and corticalization of the trabecular tissue. The volumetric density of cortical bone rose by 2.2 ± 15.8% (p < 0.1), and that of trabecular bone decreased by 2.6 ± 10.7% (p < 0.01). The combined changes in both bone volume and density in the exercise group were associated with marked increase in cortical BMC (3.1 ± 10.7%, p < 0.01) and decrease in trabecular BMC (−3.4 ± 14.2%, p < 0.05), which were statistically different from those observed in the control group (p < 0.05). In conclusion, these results confirm that site-specific moderate physical exercises have very little effect on bone mass. However, it appears that some exercises may reshape the bone segment under stress by increasing both the cross-sectional area and the density of the cortical component. These structural changes are theoretically associated with increases in the bending strength. (J Bone Miner Res 1999;14:120-124)

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Section: Discussionmentioning

confidence: 99%

Site-Specific Effects of Strength Training on Bone Structure and Geometry of Ultradistal Radius in Postmenopausal Women

Адами

Gatti

Braga

et al. 1999

Journal of Bone and Mineral Research

146

129

View full text Add to dashboard Cite

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“…The tissue was modeled as a continuum, thereby neglecting the microscopic architecture of cortical bone. The anisotropy of the bone matrix was taken into account by applying elasticity (from Reilly and Burstein, 1975): Akhter et al (1992): n 23 ¼ 0.41, n 12 ¼ n 13 ¼ 0.38), and permeability (adapted from Dillaman et al (1991):…”

Section: Calculation Of Fluid Velocitiesmentioning

confidence: 99%

A Finite Element Analysis for the Prediction of Load-induced Fluid Flow and Mechanochemical Transduction in Bone

Steck

Niederer

Tate

2003

Journal of Theoretical Biology

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“…As a result, at least in some of the cases, the opercular response in the area between the screws could be the result of a rather complex combination of spring-induced compression, contact pressure on the surface of the bone and muscle forces. Previous studies in rats (Akhter et al, 1992;Turner et al, 1991) have shown that external 4-point bending of the tibia produces a significant periosteal reaction in the form of woven bone deposition on both the periosteal and endosteal surfaces. This loading was compared with simple periosteal pressure without a bending moment, which produced far less periosteal new bone formation and none on the endosteum (Akhter et al, 1998).…”

Section: Discussionmentioning

confidence: 97%

The response of anosteocytic bone to controlled loading

Atkins

Milgram

Weiner

et al. 2015

Journal of Experimental Biology

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The bones of the skeleton of most advanced teleost fish do not contain osteocytes. Considering the pivotal role assigned to osteocytes in the process of modeling and remodeling (the adaptation of external and internal bone structure and morphology to external loads and the repair of areas with micro-damage accumulation, respectively) it is unclear how, and even whether, their skeleton can undergo modeling and remodeling. Here, we report on the results of a study of controlled loading of the anosteocytic opercula of tilapia (Oreochromis aureus). Using a variety of microscopy techniques we show that the bone of the anosteocytic tilapia actively adapts to applied loads, despite the complete absence of osteocytes. We show that in the directly loaded area, the response involves a combination of bone resorption and bone deposition; we interpret these results and the structure of the resultant bone tissue to mean that both modeling and remodeling are taking place in response to load. We further show that adjacent to the loaded area, new bone is deposited in an organized, layered manner, typical of a modeling process. The material stiffness of the newly deposited bone is higher than that of the bone which was present prior to loading. The absence of osteocytes requires another candidate cell for mechanosensing and coordinating the modeling process, with osteoblasts seeming the most likely candidates.

show abstract

Characterization of in vivo strain in the rat tibia during external application of a four-point bending load

Cited by 85 publications

References 15 publications

Site-Specific Effects of Strength Training on Bone Structure and Geometry of Ultradistal Radius in Postmenopausal Women

Site-Specific Effects of Strength Training on Bone Structure and Geometry of Ultradistal Radius in Postmenopausal Women

A Finite Element Analysis for the Prediction of Load-induced Fluid Flow and Mechanochemical Transduction in Bone

The response of anosteocytic bone to controlled loading

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