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The influence of gap size on the development of fracture union with a micro external fixator

Research output: Contribution to journalArticle

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The influence of gap size on the development of fracture union with a micro external fixator. / Meeson, Richard; Moazen, Mehran; Sanghani-Kerai, Anita; Osagie-Clouard, Liza; Coathup, Melanie; Blunn, Gordon.

In: Journal of the Mechanical Behavior of Biomedical Materials, Vol. 99, 01.11.2019, p. 161-168.

Research output: Contribution to journalArticle

Harvard

Meeson, R, Moazen, M, Sanghani-Kerai, A, Osagie-Clouard, L, Coathup, M & Blunn, G 2019, 'The influence of gap size on the development of fracture union with a micro external fixator', Journal of the Mechanical Behavior of Biomedical Materials, vol. 99, pp. 161-168. https://doi.org/10.1016/j.jmbbm.2019.07.015

APA

Meeson, R., Moazen, M., Sanghani-Kerai, A., Osagie-Clouard, L., Coathup, M., & Blunn, G. (2019). The influence of gap size on the development of fracture union with a micro external fixator. Journal of the Mechanical Behavior of Biomedical Materials, 99, 161-168. https://doi.org/10.1016/j.jmbbm.2019.07.015

Vancouver

Meeson R, Moazen M, Sanghani-Kerai A, Osagie-Clouard L, Coathup M, Blunn G. The influence of gap size on the development of fracture union with a micro external fixator. Journal of the Mechanical Behavior of Biomedical Materials. 2019 Nov 1;99:161-168. https://doi.org/10.1016/j.jmbbm.2019.07.015

Author

Meeson, Richard ; Moazen, Mehran ; Sanghani-Kerai, Anita ; Osagie-Clouard, Liza ; Coathup, Melanie ; Blunn, Gordon. / The influence of gap size on the development of fracture union with a micro external fixator. In: Journal of the Mechanical Behavior of Biomedical Materials. 2019 ; Vol. 99. pp. 161-168.

Bibtex

@article{5a42f9076b7447528ffeb4c62a84c776,
title = "The influence of gap size on the development of fracture union with a micro external fixator",
abstract = "Increasingly, the rat femoral fracture model is being used for preclinical investigations of fracture healing, however, the effect of gap size and its influence on mechanobiology is not well understood. We aimed to evaluate the influence of osteotomy gap on osteotomy healing between the previously published extremes of guaranteed union (0.5 mm) and non-union (3 mm) using this model.A femoral osteotomy in 12–14 week old female Wistar rats was stabilised with a micro fixator (titanium blocks, carbon fiber bars) with an osteotomy gap of 1.0 mm (n = 5), 1.5 mm (n = 7), 2.0 mm (n = 6). After five weeks, the left femur was retrieved. The osteotomy gap was scanned using X-ray microtomography and then histologically evaluated. The radiographic union rate (complete mineralised bone bridging across the osteotomy) was three times higher for the 1.0 mm than the 2.0 mm gap. The 1.0 mm gap had the largest callus (0.069μm3) and bone volume (0.035μm3). Callus and bone volume were approximately 50{\%} smaller within the 2.0 mm gap.Using cadaveric rat femurs stabilised with the external fixator, day 0 mechanical assessment of construct stiffness was calculated on materials testing machine displacement vs load output. The construct stiffness for the 1.0, 1.5 and 2.0 mm gaps was 32.6 ± 5.4, 32.5 ± 2.4, and 32.4 ± 8.3 N/mm (p = 0.779). Interfragmentary strain (IFS) was calculated using the change in osteotomy gap displacement as measured using microstrain miniature differential reluctance transducer spanning the osteotomy gap. Increasing the gap size significantly reduced the IFS (p = 0.013). The mean ‘day 0’ IFS for the 1.0, 1.5 and 2.0 mm gaps were 11.2 ± 1.3, 8.4 ± 1.5 and 6.1 ± 1.2{\%} respectively.A 1.5 mm gap resulted in a delayed fracture healing by 5 weeks and may represent a useful test environment for fracture healing therapy. Increasing gap size did not affect construct stiffness, but did reduce the ‘day 0’ IFS, with a doubling of non-union and halving of bone volume measured between 1.0 and 2.0 mm gaps.",
keywords = "RCUK, MRC, MR/N002318/1",
author = "Richard Meeson and Mehran Moazen and Anita Sanghani-Kerai and Liza Osagie-Clouard and Melanie Coathup and Gordon Blunn",
year = "2019",
month = "11",
day = "1",
doi = "10.1016/j.jmbbm.2019.07.015",
language = "English",
volume = "99",
pages = "161--168",
journal = "Journal of the Mechanical Behavior of Biomedical Materials",
issn = "1751-6161",
publisher = "Elsevier BV",

}

RIS

TY - JOUR

T1 - The influence of gap size on the development of fracture union with a micro external fixator

AU - Meeson, Richard

AU - Moazen, Mehran

AU - Sanghani-Kerai, Anita

AU - Osagie-Clouard, Liza

AU - Coathup, Melanie

AU - Blunn, Gordon

PY - 2019/11/1

Y1 - 2019/11/1

N2 - Increasingly, the rat femoral fracture model is being used for preclinical investigations of fracture healing, however, the effect of gap size and its influence on mechanobiology is not well understood. We aimed to evaluate the influence of osteotomy gap on osteotomy healing between the previously published extremes of guaranteed union (0.5 mm) and non-union (3 mm) using this model.A femoral osteotomy in 12–14 week old female Wistar rats was stabilised with a micro fixator (titanium blocks, carbon fiber bars) with an osteotomy gap of 1.0 mm (n = 5), 1.5 mm (n = 7), 2.0 mm (n = 6). After five weeks, the left femur was retrieved. The osteotomy gap was scanned using X-ray microtomography and then histologically evaluated. The radiographic union rate (complete mineralised bone bridging across the osteotomy) was three times higher for the 1.0 mm than the 2.0 mm gap. The 1.0 mm gap had the largest callus (0.069μm3) and bone volume (0.035μm3). Callus and bone volume were approximately 50% smaller within the 2.0 mm gap.Using cadaveric rat femurs stabilised with the external fixator, day 0 mechanical assessment of construct stiffness was calculated on materials testing machine displacement vs load output. The construct stiffness for the 1.0, 1.5 and 2.0 mm gaps was 32.6 ± 5.4, 32.5 ± 2.4, and 32.4 ± 8.3 N/mm (p = 0.779). Interfragmentary strain (IFS) was calculated using the change in osteotomy gap displacement as measured using microstrain miniature differential reluctance transducer spanning the osteotomy gap. Increasing the gap size significantly reduced the IFS (p = 0.013). The mean ‘day 0’ IFS for the 1.0, 1.5 and 2.0 mm gaps were 11.2 ± 1.3, 8.4 ± 1.5 and 6.1 ± 1.2% respectively.A 1.5 mm gap resulted in a delayed fracture healing by 5 weeks and may represent a useful test environment for fracture healing therapy. Increasing gap size did not affect construct stiffness, but did reduce the ‘day 0’ IFS, with a doubling of non-union and halving of bone volume measured between 1.0 and 2.0 mm gaps.

AB - Increasingly, the rat femoral fracture model is being used for preclinical investigations of fracture healing, however, the effect of gap size and its influence on mechanobiology is not well understood. We aimed to evaluate the influence of osteotomy gap on osteotomy healing between the previously published extremes of guaranteed union (0.5 mm) and non-union (3 mm) using this model.A femoral osteotomy in 12–14 week old female Wistar rats was stabilised with a micro fixator (titanium blocks, carbon fiber bars) with an osteotomy gap of 1.0 mm (n = 5), 1.5 mm (n = 7), 2.0 mm (n = 6). After five weeks, the left femur was retrieved. The osteotomy gap was scanned using X-ray microtomography and then histologically evaluated. The radiographic union rate (complete mineralised bone bridging across the osteotomy) was three times higher for the 1.0 mm than the 2.0 mm gap. The 1.0 mm gap had the largest callus (0.069μm3) and bone volume (0.035μm3). Callus and bone volume were approximately 50% smaller within the 2.0 mm gap.Using cadaveric rat femurs stabilised with the external fixator, day 0 mechanical assessment of construct stiffness was calculated on materials testing machine displacement vs load output. The construct stiffness for the 1.0, 1.5 and 2.0 mm gaps was 32.6 ± 5.4, 32.5 ± 2.4, and 32.4 ± 8.3 N/mm (p = 0.779). Interfragmentary strain (IFS) was calculated using the change in osteotomy gap displacement as measured using microstrain miniature differential reluctance transducer spanning the osteotomy gap. Increasing the gap size significantly reduced the IFS (p = 0.013). The mean ‘day 0’ IFS for the 1.0, 1.5 and 2.0 mm gaps were 11.2 ± 1.3, 8.4 ± 1.5 and 6.1 ± 1.2% respectively.A 1.5 mm gap resulted in a delayed fracture healing by 5 weeks and may represent a useful test environment for fracture healing therapy. Increasing gap size did not affect construct stiffness, but did reduce the ‘day 0’ IFS, with a doubling of non-union and halving of bone volume measured between 1.0 and 2.0 mm gaps.

KW - RCUK

KW - MRC

KW - MR/N002318/1

U2 - 10.1016/j.jmbbm.2019.07.015

DO - 10.1016/j.jmbbm.2019.07.015

M3 - Article

VL - 99

SP - 161

EP - 168

JO - Journal of the Mechanical Behavior of Biomedical Materials

JF - Journal of the Mechanical Behavior of Biomedical Materials

SN - 1751-6161

ER -

ID: 14965691