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The influence of foramina on femoral neck fractures and strains predicted with finite element analysis

Kok, Joeri LU orcid ; Odin, Karin ; Rokkones, Sofia ; Grassi, Lorenzo LU orcid and Isaksson, Hanna LU orcid (2022) In Journal of the Mechanical Behavior of Biomedical Materials 134.
Abstract

Hip fractures following a low-impact fall are common in the elderly. Finite element (FE) models of the proximal femur can improve the prediction of fracture risk over current clinical standards. Foramina in the femoral neck may influence its fracture mechanics, albeit the majority of FE modelling approaches do not consider them. This study aimed to show how foramina affect fracture propagation and FE strain predictions in the femoral neck. μCT images were taken of 10 cadaveric proximal femora before and after fracture, following quasi-static mechanical loading representing a sideways fall. The μCT images of the fractured femora were used to determine where the bones fractured in relation to the foramina. FE models were created based on... (More)

Hip fractures following a low-impact fall are common in the elderly. Finite element (FE) models of the proximal femur can improve the prediction of fracture risk over current clinical standards. Foramina in the femoral neck may influence its fracture mechanics, albeit the majority of FE modelling approaches do not consider them. This study aimed to show how foramina affect fracture propagation and FE strain predictions in the femoral neck. μCT images were taken of 10 cadaveric proximal femora before and after fracture, following quasi-static mechanical loading representing a sideways fall. The μCT images of the fractured femora were used to determine where the bones fractured in relation to the foramina. FE models were created based on μCT and clinical CT scans of the intact femora. The superolateral side of the femoral neck was modelled with high detail including foramina. Element-specific Young's moduli were assigned and the models were solved quasi-statically. The models predicted high strains inside foramina, agreeing with experimental strain measurements. However, these high strains inside foramina were often not related to the observed fracture location. μCT images also confirmed that the foramina mostly remained intact after fracture. Using a fracture criterion based on local strain averaging improved the accuracy of the predicted fracture location as well as the correlation between the FE predicted fracture forces and the experimentally measured peak forces. To conclude, the presence of foramina can influence the fracture pattern in femoral neck fractures and inclusion of foramina in FE models improves the prediction of local strain concentrations.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Finite element modeling, Bone strength, Sideways fall, Hip fracture, Micro-CT, Quasi-static loading
in
Journal of the Mechanical Behavior of Biomedical Materials
volume
134
article number
105364
publisher
Elsevier
external identifiers
  • scopus:85135176895
  • pmid:35917637
ISSN
1751-6161
DOI
10.1016/j.jmbbm.2022.105364
language
English
LU publication?
yes
id
6045a841-bf21-41e7-a68b-e260f4df2289
date added to LUP
2022-08-08 09:51:20
date last changed
2024-06-27 19:33:52
@article{6045a841-bf21-41e7-a68b-e260f4df2289,
  abstract     = {{<p>Hip fractures following a low-impact fall are common in the elderly. Finite element (FE) models of the proximal femur can improve the prediction of fracture risk over current clinical standards. Foramina in the femoral neck may influence its fracture mechanics, albeit the majority of FE modelling approaches do not consider them. This study aimed to show how foramina affect fracture propagation and FE strain predictions in the femoral neck. μCT images were taken of 10 cadaveric proximal femora before and after fracture, following quasi-static mechanical loading representing a sideways fall. The μCT images of the fractured femora were used to determine where the bones fractured in relation to the foramina. FE models were created based on μCT and clinical CT scans of the intact femora. The superolateral side of the femoral neck was modelled with high detail including foramina. Element-specific Young's moduli were assigned and the models were solved quasi-statically. The models predicted high strains inside foramina, agreeing with experimental strain measurements. However, these high strains inside foramina were often not related to the observed fracture location. μCT images also confirmed that the foramina mostly remained intact after fracture. Using a fracture criterion based on local strain averaging improved the accuracy of the predicted fracture location as well as the correlation between the FE predicted fracture forces and the experimentally measured peak forces. To conclude, the presence of foramina can influence the fracture pattern in femoral neck fractures and inclusion of foramina in FE models improves the prediction of local strain concentrations.</p>}},
  author       = {{Kok, Joeri and Odin, Karin and Rokkones, Sofia and Grassi, Lorenzo and Isaksson, Hanna}},
  issn         = {{1751-6161}},
  keywords     = {{Finite element modeling; Bone strength; Sideways fall; Hip fracture; Micro-CT; Quasi-static loading}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Journal of the Mechanical Behavior of Biomedical Materials}},
  title        = {{The influence of foramina on femoral neck fractures and strains predicted with finite element analysis}},
  url          = {{http://dx.doi.org/10.1016/j.jmbbm.2022.105364}},
  doi          = {{10.1016/j.jmbbm.2022.105364}},
  volume       = {{134}},
  year         = {{2022}},
}