Computational modelling of ovine critical-sized tibial defects with implanted scaffolds and prediction of the safety of fixator removal

J Mech Behav Biomed Mater. 2015 Apr:44:133-46. doi: 10.1016/j.jmbbm.2015.01.008. Epub 2015 Jan 14.

Abstract

Computational model geometries of tibial defects with two types of implanted tissue engineering scaffolds, β-tricalcium phosphate (β-TCP) and poly-ε-caprolactone (PCL)/β-TCP, are constructed from µ-CT scan images of the real in vivo defects. Simulations of each defect under four-point bending and under simulated in vivo axial compressive loading are performed. The mechanical stability of each defect is analysed using stress distribution analysis. The results of this analysis highlights the influence of callus volume, and both scaffold volume and stiffness, on the load-bearing abilities of these defects. Clinically-used image-based methods to predict the safety of removing external fixation are evaluated for each defect. Comparison of these measures with the results of computational analyses indicates that care must be taken in the interpretation of these measures.

Keywords: Critical sized defect; Defect stability; External fixator; Orthopaedic scaffold; PCL; β-tricalcium phosphate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Phosphates
  • Compressive Strength
  • Computer Simulation*
  • Elasticity
  • External Fixators*
  • Finite Element Analysis
  • Materials Testing*
  • Polyesters
  • Safety*
  • Sheep*
  • Stress, Mechanical
  • Tibia / diagnostic imaging
  • Tibia / injuries*
  • Tissue Engineering
  • Tissue Scaffolds*
  • Weight-Bearing
  • X-Ray Microtomography

Substances

  • Calcium Phosphates
  • Polyesters
  • beta-tricalcium phosphate
  • polycaprolactone