Elucidating failure mechanisms in human femurs during a fall to the side using bilateral digital image correlation
Grassi, Lorenzo LU
; Kok, Joeri
LU
; Gustafsson, Anna
LU
; Zheng, Yi
; Väänänen, Sami P.
; Jurvelin, Jukka S.
and Isaksson, Hanna
LU
(2020)
In Journal of Biomechanics
106.
- Abstract
An improved understanding of the mechanical properties of human femurs is a milestone towards a more accurate assessment of fracture risk. Digital image correlation (DIC) has recently been adopted to provide full-field strain measurements during mechanical testing of femurs. However, it has typically been used to measure strains on the anterior side of the femur, whereas in both single-leg-stance and sideways fall loading conditions, the highest deformations result on the medial and lateral sides of the femoral neck. The goal of this study was to measure full-field deformations simultaneously on the medial and lateral side of the femoral neck in a configuration resembling a fall to the side. Twelve female cadaver femurs were prepared... (More)
An improved understanding of the mechanical properties of human femurs is a milestone towards a more accurate assessment of fracture risk. Digital image correlation (DIC) has recently been adopted to provide full-field strain measurements during mechanical testing of femurs. However, it has typically been used to measure strains on the anterior side of the femur, whereas in both single-leg-stance and sideways fall loading conditions, the highest deformations result on the medial and lateral sides of the femoral neck. The goal of this study was to measure full-field deformations simultaneously on the medial and lateral side of the femoral neck in a configuration resembling a fall to the side. Twelve female cadaver femurs were prepared for DIC measurements and tested in sideways fall at 5 mm/s displacement rate. Two pairs of cameras recorded the medial and lateral side of the femoral neck, and deformations were calculated using DIC. The samples exhibited a two-stage failure: first, a compressive collapse on the superolateral side of the femoral neck in conjunction with peak force, followed by complete femoral neck fracture at the force drop following the post-elastic phase. DIC measurements corroborated this observation by reporting no tensile strains above yield limit for the medial side of the neck up to peak force. DIC measurements registered onto the bone micro-architecture showed strain localizations in proximity of cortical pores due to, for instance, blood vessels. This could explain previously reported discrepancies between simulations and experiments in regions rich with large pores, like the superolateral femoral neck.
(Less)
- author
- Grassi, Lorenzo
LU
; Kok, Joeri
LU
; Gustafsson, Anna
LU
; Zheng, Yi
; Väänänen, Sami P.
; Jurvelin, Jukka S.
and Isaksson, Hanna
LU
- organization
- publishing date
- 2020
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Digital image correlation, Direction of principal strain, Femurs, Hip fractures, Mechanical testing, Sideways fall, Strain distribution
- in
- Journal of Biomechanics
- volume
- 106
- article number
- 109826
- publisher
- Elsevier
- external identifiers
-
- pmid:32517988
- scopus:85085087804
- ISSN
- 0021-9290
- DOI
- 10.1016/j.jbiomech.2020.109826
- language
- English
- LU publication?
- yes
- id
- 5ac48516-8412-4a8a-965f-3dde67552a49
- date added to LUP
- 2020-06-12 13:14:55
- date last changed
- 2024-04-17 09:46:30
@article{5ac48516-8412-4a8a-965f-3dde67552a49,
abstract = {{<p>An improved understanding of the mechanical properties of human femurs is a milestone towards a more accurate assessment of fracture risk. Digital image correlation (DIC) has recently been adopted to provide full-field strain measurements during mechanical testing of femurs. However, it has typically been used to measure strains on the anterior side of the femur, whereas in both single-leg-stance and sideways fall loading conditions, the highest deformations result on the medial and lateral sides of the femoral neck. The goal of this study was to measure full-field deformations simultaneously on the medial and lateral side of the femoral neck in a configuration resembling a fall to the side. Twelve female cadaver femurs were prepared for DIC measurements and tested in sideways fall at 5 mm/s displacement rate. Two pairs of cameras recorded the medial and lateral side of the femoral neck, and deformations were calculated using DIC. The samples exhibited a two-stage failure: first, a compressive collapse on the superolateral side of the femoral neck in conjunction with peak force, followed by complete femoral neck fracture at the force drop following the post-elastic phase. DIC measurements corroborated this observation by reporting no tensile strains above yield limit for the medial side of the neck up to peak force. DIC measurements registered onto the bone micro-architecture showed strain localizations in proximity of cortical pores due to, for instance, blood vessels. This could explain previously reported discrepancies between simulations and experiments in regions rich with large pores, like the superolateral femoral neck.</p>}},
author = {{Grassi, Lorenzo and Kok, Joeri and Gustafsson, Anna and Zheng, Yi and Väänänen, Sami P. and Jurvelin, Jukka S. and Isaksson, Hanna}},
issn = {{0021-9290}},
keywords = {{Digital image correlation; Direction of principal strain; Femurs; Hip fractures; Mechanical testing; Sideways fall; Strain distribution}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Journal of Biomechanics}},
title = {{Elucidating failure mechanisms in human femurs during a fall to the side using bilateral digital image correlation}},
url = {{https://lup.lub.lu.se/search/files/103417832/2020_109826_JBiomech.pdf}},
doi = {{10.1016/j.jbiomech.2020.109826}},
volume = {{106}},
year = {{2020}},
}