Development of a balanced experimental–computational approach to understanding the mechanics of proximal femur fractures

Helgason, B.; Gilchrist, S.; Ariza, O.; Chak, J.D.; Zheng, Guoyan; Widmer, R.P.; Ferguson, S.J.; Guy, P.; Cripton, P.A.; Helgason, Benedikt (2014). Development of a balanced experimental–computational approach to understanding the mechanics of proximal femur fractures. Medical engineering & physics, 36(6), pp. 793-799. Elsevier 10.1016/j.medengphy.2014.02.019

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The majority of people who sustain hip fractures after a fall to the side would not have been identified using current screening techniques such as areal bone mineral density. Identifying them, however, is essential so that appropriate pharmacological or lifestyle interventions can be implemented. A protocol, demonstrated on a single specimen, is introduced, comprising the following components; in vitro biofidelic drop tower testing of a proximal femur; high-speed image analysis through digital image correlation; detailed accounting of the energy present during the drop tower test; organ level finite element simulations of the drop tower test; micro level finite element simulations of critical volumes of interest in the trabecular bone. Fracture in the femoral specimen initiated in the superior part of the neck. Measured fracture load was 3760 N, compared to 4871 N predicted based on the finite element analysis. Digital image correlation showed compressive surface strains as high as 7.1% prior to fracture. Voxel level results were consistent with high-speed video data and helped identify hidden local structural weaknesses. We found using a drop tower test protocol that a femoral neck fracture can be created with a fall velocity and energy representative of a sideways fall from standing. Additionally, we found that the nested explicit finite element method used allowed us to identify local structural weaknesses associated with femur fracture initiation.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute for Surgical Technology & Biomechanics ISTB [discontinued]

UniBE Contributor:

Zheng, Guoyan and Helgason, Benedikt

Subjects:

500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health

ISSN:

1350-4533

Publisher:

Elsevier

Language:

English

Submitter:

Guoyan Zheng

Date Deposited:

01 May 2015 16:25

Last Modified:

25 Nov 2015 10:49

Publisher DOI:

10.1016/j.medengphy.2014.02.019

BORIS DOI:

10.7892/boris.67986

URI:

https://boris.unibe.ch/id/eprint/67986

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