Biomechanical bone remodeling

Chun Hoe Ong

11/12/2012

BIEN 430

Mechanical damage fatigue dynamics coupled with bone cell activities in creating bone remodeling models.

What is being modeled? The modulus of elasticity as a function of

porosity

What is being changed? Porosity Function

Matlab

Matlab: used as the primary means of recreating the positive control model.

Microsoft Excel

Excel: used to validate Matlab’s plots and to recreate equations.

Equation 1

Where E = Young’s modulusp= Porosity

Equation 2

Where s= Specific Area

p= Porosity

Equation 3

Where E= Absolute Young’s Modulusp= Porosity

Positive Control

Plot of Elastic Modulus versus Porosity Plot of Specific Area versus Porosity

Physiological Change of Positive Control

Graph of E(p) versus Specific Area (0<p<0.4)

Graph of E(p) versus Specific Area (0.4<p<1)

Bone is dynamic tissue that adepts its microstructure to its physiological and mechanical environment. (Consistent with Wolff’s Law)

The original model allows us to determine the optimal porosity to obtain the maximum elastic modulus.

Can be used to study long-term effects of mechanical damage on bone recovery.

Provides a method of predicting when a bone might fracture.

Can be used in combination of finite element code to asses strategies for knee replacement.

Significance of New Model Provides a more accurate method of

analyzing bone fractures Demonstrates the effects of change in

specific area on the elastic modulus of bone. Allows for a better prediction of bone

recovery rate

Unexpected Results The modulus of elasticity began to increase

as the surface area increased beyond 2.6m-1

for porosity> 0.4

The exponential increase of the Young’s modulus once the surface area increased beyond 2.6m-1 for porosity> 0.4