Predicting the external formation of a bone fracture callus: an optimisation approach

Abstract

The formation of a fracture callus in vivo tends to form in a structurally efficient manner distributing tissues where mechanical stimulus persists. Therefore, it is proposed that the formation of a fracture callus can be modelled in silico by way of an optimisation algorithm. This was tested by generating a finite element model of a transversal bone fracture embedded in a large tissue domain which was subjected to axial, bending and torsional loads. It was found that the relative fragment motion induced a compressive strain field in the early callus tissue which could be utilised to simulate the formation of external callus structures through an iterative optimisation process of tissue maintenance and removal. The phenomenological results showed a high level of congruence with in vivo healing patterns found in the literature. Consequently, the proposed strategy shows potential as a means of predicting spatial bone healing phenomena for pre-clinical testing.

Keywords:

• bone fracture
• callus formation
• optimisation
• simulation
• mechanical stimulus
• compressive strain field

Acknowledgements

This study was kindly funded by the Irish Research Council for Science, Engineering and Technology (IRCSET) under the postgraduate research awards scheme, funded by the Irish Government's National Development Plan. Scholarship Reference Number: RS/2005/25.