Heterotopic ossification (HO) is the formation of mature lamellar bone in tissues that are not usually osseous. It is a significant risk in blast-related injuries and is seen in approximately 60% of UK military blast-related amputees. HO can result in reduced range of motion, pain, nerve impingement and can affect prosthesis fitting. The causes of HO are due to a mix of mechanical and biological, local and systemic factors. However, as with normal bone formation and remodelling, it may be expected that heterotopic bone also responds to mechanical stimuli to an extent. Understanding this relationship further can give insight into possible ways to manipulate the progression of HO and prevent complications in the future. The objective of this research is to create a mechanically driven physiological computational model of HO in the residual limb of a trans-femoral amputee. The current work involved expanding upon previously proposed finite element bone remodelling algorithms in the literature for the application of heterotopic remodelling in soft tissue. This study introduced an extra factor to represent the tendency for soft tissue to calcify. This factor increases in magnitude with proximity to a specified wound site and with tissue strain. Initially, soft tissue is modelled as hypoelastic with a much lower stiffness to bone. If the density in a soft tissue element exceeds a certain threshold, the material properties of the element are redefined to become proportional to the density alike bone. These newly recruited bone elements make up the projected heterotopic bone geometry. The different parameters within the algorithm were adjusted to examine their effect on the final outcome of heterotopic bone geometry. With consideration to their effects, loading was found to significantly alter the geometry of HO. Certain characteristic appearances of HO outlined in the literature were reproduced by adjusting the loading environment.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:733165 |
| Date | January 2017 |
| Creators | Rosenberg, Naomi |
| Contributors | Bull, Anthony |
| Publisher | Imperial College London |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/10044/1/55101 |
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