An independent ‘post-mortem’ calibration of electrical resistance strain gauges bonded to bone surfaces ‘in vivo’

Baggott, D.G.; Lanyon, Lance E.

doi:10.1016/0021-9290(77)90061-6

Cited by 28 publications

(7 citation statements)

References 7 publications

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“…These measurements have also been carried out "in vivo" on various animals (Lanyon, 1972, on the sheep vertebrae; Lanyon, 1973, on the sheep calcaneus; Baggott and Lanyon, 1977, on the sheep and goat radius; Carter et al, 1980, on the canine radius and ulna; Caler et al, 1981, on the canine radius and femur). This method is based on variation in the electric signal of transducers (electric strain gauges) secured to the bones, this variation being proportional to the strains which the transducers undergo when the bone is loaded.…”

mentioning

confidence: 99%

Development of a method for quantitative stress analysis in bones by three‐dimensional photoelasticity

et al. 1983

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Comparative critical examination of methods suitable for studying stress in bones have shown that the three-dimensional photoelastic method is one of the most reliable. Described herein is the method for obtaining, by fusion, full-scale models in epoxy resin, that are exactly equivalent to external shape of the prototypes.This technique offers the advantages of being applicable without variation to any bone segment and of enabling a large number of additional resin castings to be made from the same mould. Hence it is possible to produce a very large number of copies of the same bone segment that will be suitable for comparative studies of different load situations.As an example, quantitative data expressing both surface and internal tension trends in the proximal third of a normal human femur are given.It is well known that a bone exposed to mechanical stress becomes elastically deformed and develops corresponding internal tensions which, influencing its biodynamics, improve the bone structure, making it mechanically better suited for the stresses applied. The internal structure of bones thus is in direct relation to the mechanical stresses exerted on them.The correlation between mechanical requirements and bone structure, with particular reference to the arrangement and orientation of cancellous bone trabecules, has been known since early in the last century. Ward (1838) was the first to provide detailed description of cancellous bone in the femoral neck, by identifying the three main trabecular systems; furthermore, comparing the construction of femur epiphysis to that of a crane, he identified a zone subjected to compression along the medial cortical bone and a zone of tension along the lateral cortical bone. These results were later confirmed by Wyman (1857). Humphry (1858) observed that in the femoral neck the main trabecular systems cross each other at right angles, and that the trabeculae are arranged perpendicularly in relation to the articular surface of the femur head. In 1867 von Meyer published, according to data of Culmann (1866), his theory regarding cancellous bone architecture, with a definition of trabecular trajectories arranged along the principal stress lines.On the basis of Meyer's and Culmann's data, the close relationship between the function and architecture of cancellous bone was demonstrated by Wolff (1892), and developed and confirmed by Roux (1893) in his theory of functional adaptation.More recently the now undisputed link between shape, structure, and mechanical function of bone has been verified in a series of studies which have used more sophisticated and accurate methods of investigation. Among these, the most reliable are: finite elements (theoretical calculation method), electric strain gauges, brittle coatings, holographic interferometry, and photoelasticity methods (all experimental methods).The finite elements method applied to bones (Zinkiewicz,

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confidence: 99%

Development of a method for quantitative stress analysis in bones by three‐dimensional photoelasticity

et al. 1983

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“…To ensure that the strain applied to bone cells in vitro is physiologically relevant and comparable to strain received in vivo, electrical strain gauges have been used to validate the direct measurement of surface bone strain in vivo and ex vivo between 2000-4000 me. [19][20][21] Described herein are two of the most widely used models, the commercially available FlexCell tension system and the four-point bending model.…”

Section: Substrate Strainmentioning

confidence: 99%

“…The protocol for loading osteoblasts has been optimized so that physiological levels of strain [19][20][21] can be applied to cultured cells in vitro. The optimized protocol for loading osteoblasts has a waveform in each strain cycle that consists of a tamped 1 Hz square wave, with strain rates on and off of 23 000 me s À 1 generating a peak strain of 3400 me.…”

Section: Four-point Bending Modelmentioning

confidence: 99%

“…15,16 Physiologically relevant levels of fluid shear stress (FSS) around osteocyte processes in mature bone are predicted to be 8-30 dyn cm 2 , 17,18 making anything outside this range potentially pathological. Physiologically relevant levels of substrate strain have been measured as 2000-4000 me, [19][20][21] with anything above 5000 me causing periosteal woven bone formation and anything below 200 me (i.e. from microgravity conditions) causing bone loss, 22,23 although lower strain thresholds may be required for wound healing.…”

Section: Introductionmentioning

confidence: 99%

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Preclinical models for in vitro mechanical loading of bone-derived cells

Delaine-Smith¹,

Javaheri²,

Edwards³

et al. 2015

BoneKEy Reports

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It is well established that bone responds to mechanical stimuli whereby physical forces are translated into chemical signals between cells, via mechanotransduction. It is difficult however to study the precise cellular and molecular responses using in vivo systems. In vitro loading models, which aim to replicate forces found within the bone microenvironment, make the underlying processes of mechanotransduction accessible to the researcher. Direct measurements in vivo and predictive modeling have been used to define these forces in normal physiological and pathological states. The types of mechanical stimuli present in the bone include vibration, fluid shear, substrate deformation and compressive loading, which can all be applied in vitro to monolayer and three-dimensional (3D) cultures. In monolayer, vibration can be readily applied to cultures via a low-magnitude, high-frequency loading rig. Fluid shear can be applied to cultures in multiwell plates via a simple rocking platform to engender gravitational fluid movement or via a pump to cells attached to a slide within a parallel-plate flow chamber, which may be micropatterned for use with osteocytes. Substrate strain can be applied via the vacuum-driven FlexCell system or via a four-point loading jig. 3D cultures better replicate the bone microenvironment and can also be subjected to the same forms of mechanical stimuli as monolayer, including vibration, fluid shear via perfusion flow, strain or compression. 3D cocultures that more closely replicate the bone microenvironment can be used to study the collective response of several cell types to loading. This technical review summarizes the methods for applying mechanical stimuli to bone cells in vitro.

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“…The equine MC3, unlike most long bones, is loaded primarily in compression (Biewener et al 1983). Previous reported tests of gauge function ex vivo in other bones in other species (Lanyon and Smith 1970;Lanyon 1971;Cochran 1972;Baggott and Lanyon 1977;Keller and Spengler 1982), either disturbed the bone surface, assumed strain similarity between subsequent tests, or only tested the gauges in tension. None of these authors reported compressive tests of gauges that had previously recorded strains exceeding -4000 µε in vivo.…”

Section: Introductionmentioning

confidence: 99%

Ex vivo calibration and validation of in vivo equine bone strain measures

Davies

2009

Equine Veterinary Journal

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Similarities between recordings from gauges used in vivo and new gauges confirmed the reliability and likely accuracy (or possible underestimate) of very high strains (exceeding -6000 microepsilon) recorded in exercising Thoroughbred racehorses. The similarity between E(bt) and E(m) confirms that the gauges measured the true distortion of the bone in the MTS. These results confirm that mammalian bone may withstand much greater compressive loads than -4000 microepsilon under some conditions at least.

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An independent ‘post-mortem’ calibration of electrical resistance strain gauges bonded to bone surfaces ‘in vivo’

Cited by 28 publications

References 7 publications

Development of a method for quantitative stress analysis in bones by three‐dimensional photoelasticity

Development of a method for quantitative stress analysis in bones by three‐dimensional photoelasticity

Preclinical models for in vitro mechanical loading of bone-derived cells

Ex vivo calibration and validation of in vivo equine bone strain measures

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