Design, characterisation and in vivo testing of a new, adjustable stiffness, external fixator for the rat femur

V. Glatt, Christopher H Evans, R. Matthys

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Very little is known about the influence of the mechanical environment on the healing of large segmental defects. This partly reflects the lack of standardised, well characterized technologies to enable such studies. Here we report the design, construction and characterisation of a novel external fixator for use in conjunction with rat femoral defects. This device not only imposes a predetermined axial stiffness on the lesion, but also enables the stiffness to be changed during the healing process. The main frame of the fixator consists of polyethylethylketone with titanium alloy mounting pins. The stiffness of the fixator is determined by interchangeable connection elements of different thicknesses. Fixators were shown to stabilise 5 mm femoral defects in rats in vivo for at least 8 weeks during unrestricted cage activity. No distortion or infections, including pin infections, were noted. The healing process was simulated in vitro by inserting into a 5 mm femoral defect, materials whose Young's moduli approximated those of the different tissues present in regenerating bone. These studies confirmed that, although the external fixator is the major determinant of axial stiffness during the early phase of healing, the regenerate within the lesion subsequently dominates this property. There is much clinical interest in altering the mechanics of the defect to enhance bone healing. Our data suggest that, if alteration of the mechanical environment is to be used to modulate the healing of large segmental defects, this needs to be performed before the tissue properties become dominant.

Original languageEnglish (US)
Pages (from-to)289-299
Number of pages11
JournalEuropean Cells and Materials
Volume23
StatePublished - Jan 2012
Externally publishedYes

Fingerprint

External Fixators
Thigh
Femur
Rats
Stiffness
Defects
Testing
Bone and Bones
Elastic Modulus
Infection
Titanium
Mechanics
Bone
Tissue
Technology
Equipment and Supplies
Mountings
Titanium alloys
Elastic moduli

Keywords

  • Bone healing
  • Dynamisation
  • External fixator
  • Mechanical stiffness
  • Mechanobiology
  • Small animal model

ASJC Scopus subject areas

  • Biochemistry
  • Cell Biology
  • Bioengineering
  • Biomedical Engineering
  • Biomaterials
  • Medicine(all)

Cite this

Design, characterisation and in vivo testing of a new, adjustable stiffness, external fixator for the rat femur. / Glatt, V.; Evans, Christopher H; Matthys, R.

In: European Cells and Materials, Vol. 23, 01.2012, p. 289-299.

Research output: Contribution to journalArticle

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