Examination of compact bone microdamage using back-scattered electron microscopy

Schaffler, Mitchell B.; Pitchford, W. C.; Choi, Kuiwon; Riddle, Jeanne M.

doi:10.1016/8756-3282(94)90271-2

Cited by 132 publications

(116 citation statements)

References 11 publications

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“…Samples were prepared for examination in a scanning electron microscope (SEM) using a staining technique developed by Schaffler et al (Schaffler et al, 1994). They were fixed in 4% paraformaldehyde solution for 24 hours at 4 o C and washed three times in phosphate buffered saline (PBS).…”

Section: Methodsmentioning

confidence: 99%

Rupture of osteocyte processes across microcracks: the effect of crack length and stress

Dooley

Tisbo

Lee

et al. 2011

Biomech Model Mechanobiol

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Bone cells are connected to one another in a network, via their dendritic cellular processes. Previously, we hypothesised that these processes could be ruptured by microcracks. We proposed this as a mechanism by which osteoctyes could detect the presence of microcracks. In order for this mechanism to be effective, the number of ruptured processes would have to increase with microcrack length and also with the applied cyclic stress applied. This paper presents for the first time experimental data which shows that this is indeed the case. We examined samples of bovine, ovine and murine bone ex vivo and observed processes passing across crack faces: some were still intact whilst others had ruptured. The number of intact processes per unit crack length decreased significantly with increasing crack length, and also decreased in samples which had been tested in vitro at higher stress levels. A theoretical model which we had developed previously was able to predict the overall magnitude and general trends in the experimental data. This work has provided further support for our "scissors" model which proposes that microcracks can be detected because they disturb the osteocyte network, specifically by rupturing cellular processes where they pass across the crack faces. AbstractBone cells are connected to one another in a network, via their dendritic cellular processes. Previously, we hypothesised that these processes could be ruptured by microcracks. We proposed this as a mechanism by which osteoctyes could detect the presence of microcracks. In order for this mechanism to be effective, the number of ruptured processes would have to increase with microcrack length and also with the applied cyclic stress applied. This paper presents for the first time experimental data which shows that this is indeed the case. We examined samples of bovine, ovine and murine bone ex vivo and observed processes passing across crack faces: some were still intact whilst others had ruptured. The number of intact processes per unit crack length decreased significantly with increasing crack length, and also decreased in samples which had been tested in vitro at higher stress levels. A theoretical model which we had developed previously was able to predict the overall magnitude and general trends in the experimental data. This work has provided further support for our "scissors" model which proposes that microcracks can be detected because they disturb the osteocyte network, specifically by rupturing cellular processes where they pass across the crack faces.

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Section: Methodsmentioning

confidence: 99%

Rupture of osteocyte processes across microcracks: the effect of crack length and stress

Dooley

Tisbo

Lee

et al. 2011

Biomech Model Mechanobiol

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“…10 transverse and 10 longitudinal specimens fr'om the right femora were packed frozen in polyethylene bags and were surrounded by dry ice in an expanded polystyrene box. The specimens were sterilized by gamma radiation within the standard sterilization dose range of [25][26][27][28][29][30][31][32][33][34][35]31]. Specifically.…”

Section: Corticalmentioning

confidence: 99%

Fracture resistance of gamma radiation sterilized cortical bone allografts

Akkuş

Rimnac

2001

Journal Orthopaedic Research

107

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Gamma radiation is widely used for sterilization of human cortical bone allografts. Previous studies have reported that cortical bone becomes brittle due to gamma radiation sterilization. This embrittlement raises concern about the performance of a radiation sterilized allograft in the presence of a stress concentration that might be surgically introduced or biologically induced. The purpose of this study was to investigate the effect of gamma radiation sterilization on the fracture resistance of human femoral cortical bone in the presence of a stress concentration. Fracture toughness tests of specimens sterilized at B dose of 27.5 kGy and control specimens were conducted transverse and longitudinal to the osteonal orientation of the bone tissue. The formation of damage was monitored with acoustic emission (AE) during testing and was histologically observed following testing. There was a significant decrease in fracture toughness due to irradiation in both crack growth directions. The work-to-fracture was also significantly reduced. It was observed that the ability of bone tissue to undergo damage in the form of microcracks and diffuse damage was significantly impaired due to radiation sterilization as evidenced by decreased AE activity and histological observations. The results of this study suggest that, for cortical bone irradiated at 27.5 kGy, it is easier to initiate and propagate a macrocrack from a stress concentration due to the inhibition of

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“…These fractures occur commonly in athletes and soldiers engaged in high intensity, repetitive activities such as marching or running. If, on the other hand, damage accumulates at 'normal' rates but the bone's repair mechanism is deficient, fragility fractures result, which occur commonly in ageing bone (Schaffler et al, 1994a(Schaffler et al, , 1995.…”

Section: Introductionmentioning

confidence: 99%

“…They hypothesised that the presence of lamellae influenced the process by which microcracks coalesced but that vascular or other naturally occurring cavities did not initiate microcracking and appeared to deflect microcracks. Schaffler et al (1994b) used back-scattered electron microscopy on fuchsin stained sections of human rib to show that features of the bone matrix ultrastructure, such as the collagen fibre-bone mineral relationship play a key role in minimising the formation of larger detrimental cracks whilst encouraging the formation of numerous small cracks which do not propagate as readily to failure. Boyce et al (1998) showed experimentally that microcracks developed in the interstitial tissue regions and stopped at the osteonal boundaries, while Schaffler et al (1995) added quantitative data to this hypothesis suggesting that 80-90% of all microcracks in cortical bone are found in the interstitial matrix between osteons.…”

Section: Introductionmentioning

confidence: 99%

Microcrack accumulation at different intervals during fatigue testing of compact bone

O’Brien

Taylor

Lee

2003

Journal of Biomechanics

191

162

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Examination of compact bone microdamage using back-scattered electron microscopy

Cited by 132 publications

References 11 publications

Rupture of osteocyte processes across microcracks: the effect of crack length and stress

Rupture of osteocyte processes across microcracks: the effect of crack length and stress

Fracture resistance of gamma radiation sterilized cortical bone allografts

Microcrack accumulation at different intervals during fatigue testing of compact bone

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