Towards understanding bone quality : Implications of reduced toughness for load-carrying ability in the presence of defects
Carlsson, Jenny LU
and Gustafsson, Anna
LU
(2025)
In Theoretical and Applied Fracture Mechanics
140.
- Abstract
Identifying patients at high risk of bone fracture is an important task. The clinical risk assessment, based on measurements of bone mass, correlates with strength but not toughness and is insufficient for reliable identification of high-risk patients. Starting from non-linear fracture mechanics, we hypothesise that reduced bone tissue fracture toughness and characteristic length, possibly in combination with increased porosity and increased microcrack prevalence, decreases the load-carrying ability which increases the risk of fracture. The hypothesis is tested using a length parameter insensitive cohesive zone phase-field method to model fracture in the presence of stress-raising defects, i.e. pores and microcracks, assuming... (More)
Identifying patients at high risk of bone fracture is an important task. The clinical risk assessment, based on measurements of bone mass, correlates with strength but not toughness and is insufficient for reliable identification of high-risk patients. Starting from non-linear fracture mechanics, we hypothesise that reduced bone tissue fracture toughness and characteristic length, possibly in combination with increased porosity and increased microcrack prevalence, decreases the load-carrying ability which increases the risk of fracture. The hypothesis is tested using a length parameter insensitive cohesive zone phase-field method to model fracture in the presence of stress-raising defects, i.e. pores and microcracks, assuming homogeneous or bone-like microstructures (osteons). Considering defects of sizes ranging from micrometres to millimetres, and similar to results obtained for other quasi-brittle materials, we find that porosity and microcracks lead to a drop in load-carrying ability proportional to the loss of cross-section if the toughness is high, but to a decrease of two thirds (in the case of pores) up to an order of magnitude (in the case of microcracks) if the toughness is low. The importance of the material properties implies that bone quality – an expression used to explain fractures unrelated to changes in bone mass – cannot be solely attributed to observable changes in porosity and amount of microcracks and underlines the role of the toughness. Moreover, the results indicate that reducing the toughness makes the crack less prone to deflect when encountering microstructural features, which is consistent with crack behaviours observed in aged bone but not in young.
(Less)
- author
- Carlsson, Jenny
LU
and Gustafsson, Anna
LU
- organization
- publishing date
- 2025-12
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Cement line, Crack initiation, Microcrack, Osteon, Phase-field cohesive zone method, Porosity
- in
- Theoretical and Applied Fracture Mechanics
- volume
- 140
- article number
- 105139
- publisher
- Elsevier
- external identifiers
-
- scopus:105012278717
- ISSN
- 0167-8442
- DOI
- 10.1016/j.tafmec.2025.105139
- project
- Fracture mechanics of bone tissue – impact of age and disease
- language
- English
- LU publication?
- yes
- additional info
- Publisher Copyright: © 2025 The Author(s)
- id
- 529d03ed-b9de-4037-9df3-6b23c44bf10f
- date added to LUP
- 2025-09-09 15:38:07
- date last changed
- 2025-10-14 12:24:38
@article{529d03ed-b9de-4037-9df3-6b23c44bf10f,
abstract = {{<p>Identifying patients at high risk of bone fracture is an important task. The clinical risk assessment, based on measurements of bone mass, correlates with strength but not toughness and is insufficient for reliable identification of high-risk patients. Starting from non-linear fracture mechanics, we hypothesise that reduced bone tissue fracture toughness and characteristic length, possibly in combination with increased porosity and increased microcrack prevalence, decreases the load-carrying ability which increases the risk of fracture. The hypothesis is tested using a length parameter insensitive cohesive zone phase-field method to model fracture in the presence of stress-raising defects, i.e. pores and microcracks, assuming homogeneous or bone-like microstructures (osteons). Considering defects of sizes ranging from micrometres to millimetres, and similar to results obtained for other quasi-brittle materials, we find that porosity and microcracks lead to a drop in load-carrying ability proportional to the loss of cross-section if the toughness is high, but to a decrease of two thirds (in the case of pores) up to an order of magnitude (in the case of microcracks) if the toughness is low. The importance of the material properties implies that bone quality – an expression used to explain fractures unrelated to changes in bone mass – cannot be solely attributed to observable changes in porosity and amount of microcracks and underlines the role of the toughness. Moreover, the results indicate that reducing the toughness makes the crack less prone to deflect when encountering microstructural features, which is consistent with crack behaviours observed in aged bone but not in young.</p>}},
author = {{Carlsson, Jenny and Gustafsson, Anna}},
issn = {{0167-8442}},
keywords = {{Cement line; Crack initiation; Microcrack; Osteon; Phase-field cohesive zone method; Porosity}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{Theoretical and Applied Fracture Mechanics}},
title = {{Towards understanding bone quality : Implications of reduced toughness for load-carrying ability in the presence of defects}},
url = {{http://dx.doi.org/10.1016/j.tafmec.2025.105139}},
doi = {{10.1016/j.tafmec.2025.105139}},
volume = {{140}},
year = {{2025}},
}