Developing a method for determining strain in trabecular

bone for validation of an FE model

Bryant RobertsSupervisors: Karen Reynolds, Egon Perilli

Background- Epidemiology of osteoporosis and fracture fixation

- What are the complications?- Flinders University Research

- How am I going to contribute?

Methods- What is strain mapping? Why is it important?- What has been done previously?- How will I accomplish my task?

Timeline- Develop strain mapping software for N specimens- How will I validate my software

Presentation Outline

Characterised by low bone mass and micro-architectural deterioration

More common in elderly women

Leading to enhanced bone fragility and a consequent increase in fracture risk

10% ↓ hip bone mass results in 2.5x greater risk of hip fracture (Klotzbuecher et al. 2000)

Osteoporosis

In Australia- Over 40 admissions to hospital daily- 16,518 incidences in 2006-07

Fracture sites- 96% neck of femur or intertrochanteric

(Dixon & Crisp, 2010)

Osteoporotic Hip Fracture

Most common surgical procedure- fixation of the fractured bone (metal

plates or screws)

Osteoporotic Hip Fracture

Low bone density results in inadequate bone-screw interface

This can lend itself to loosening of the fixation device

Implant Complications

Developing a computer-based model to increase understanding of failure mechanisms during screw insertion into trabecular bone.

Flinders University Research

FE models calculate strain as function of bone loading, architecture and assumed tissue material properties.

Trabecular bone structure - in order of µm∴ unfeasible to measure strain directly

AimUtilise strain mapping techniques currently reported within the literature.

Validating strain in FE models

Strain MappingHead Contact

Failure

Utilise software (ITK, MATLAB) to generate displacement and corresponding strain fields by application of methods defined in the literature.

If required, refine current programs for image registration

Proposal

Thank youQuestions?