Effects of Ti2448 half-pin with low elastic modulus on pin loosening in unilateral external fixation

J Mater Sci Mater Med. 2011 Jun;22(6):1579-88. doi: 10.1007/s10856-011-4313-8. Epub 2011 Apr 13.

Abstract

The objective of this study was to compare the benefits of titanium 2448 (Ti2448) half-pin and titanium-6 aluminium-4 vanadium (TAV) half-pin on reducing pin loosening during external fracture fixation. Although having similar strength, Ti2448 half-pin had even lower elastic modules (33 GPa) when compared with TAV half-pin (110 GPa), which was similar to that of cortical bone (20 GPa). In the external fixation of tibial model fractures and canine cadaveric tibia fractures, Ti2448 half-pin had greater recoverable deformation and less stress concentration at the pin-bone interface in compression, torsion, and four-points bending test. Then, tibial fractures were created in 24 dogs and stabilized with four half-pins of either Ti2448 or TAV in each animal. At 4 and 8 weeks postoperatively, fracture healing and pin loosening was assessed by radiographic grading scale. The scores of Ti2448 group were significantly higher than those of TAV group. Micro-CT analysis also indicated larger quantity and higher quality of newly formed bone at pin-bone interface in Ti2448 group. Histology observation showed the newly formed bone integrated well into the threads of Ti2448 half-pins. In contrast, there was a layer of necrotic tissue between the bone tissue and TAV half-pin at pin-bone interface in TAV group. The extraction torque values of Ti2448 half-pins near the fracture line were significantly higher than those TAV pins. In conclusion, the Ti2448 half-pin with low elastic modulus could enhance osseointegration and reduce pin loosening when compared with TAV half-pin. It is a promising biomaterial for constructing external fixation system in clinical application.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Nails*
  • Computer Simulation
  • Dogs
  • Elastic Modulus / drug effects
  • Elastic Modulus / physiology*
  • External Fixators* / adverse effects
  • Fracture Fixation* / adverse effects
  • Materials Testing / instrumentation
  • Materials Testing / methods
  • Prosthesis Failure* / drug effects
  • Stress, Mechanical
  • Tibial Fractures / diagnostic imaging
  • Tibial Fractures / pathology
  • Tibial Fractures / surgery
  • Titanium / chemistry
  • Titanium / pharmacology*
  • X-Ray Microtomography

Substances

  • Titanium