title: In vitro cyclic biomechanical properties of an interlocking equine tibial nail.
abstract: OBJECTIVE
  To determine cyclic biomechanical properties of gap osteotomized adult equine tibiae stabilized with an equine interlocking nail (EIN).
  
  
  METHODS
  In vitro experimental biomechanical investigation.
  
  
  METHODS
  Thirteen adult equine cadaveric tibiae.
  
  
  METHODS
  Adult equine tibiae with transverse, midshaft, 1-cm gap osteotomies, stabilized with an equine interlocking nail, underwent cyclic biomechanical testing in vitro under axial compression, 4-point bending, and torsion. Different specimens were subjected to different load levels that represented estimated in vivo loads at 2 Hz for 740,000 cycles. Fatigue life and gap strain were calculated.
  
  
  RESULTS
  Compression and bending, but not torsional, fatigue life were longer than time necessary for bone healing. Compressive, but not bending or torsional, gap strains were small enough to be compatible with fracture healing by primary bone formation. Gap strains for compressive, bending, and torsional loads were compatible with indirect, or secondary, bone formation.
  
  
  CONCLUSIONS
  Further modification should be made to the equine interlocking nail to increase bending stiffness and torsional fatigue life.
  
  
  CONCLUSIONS
  The stainless steel equine intramedullary interlocking nail is unlikely to provide appropriate long-term stability for fracture healing in adult equine tibiae without modifications in the nail design and material.
authors.affiliation: Department of Veterinary Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, USA.
authors.forename: L A
authors.initials: LA
authors.lastname: McDuffee
authors.forename: S M
authors.initials: SM
authors.lastname: Stover
authors.forename: K T
authors.initials: KT
authors.lastname: Taylor
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000662:veterinary*; D006736:Horses / Q000293:injuries* / Q000601:surgery*; D013978:Tibial Fractures / Q000601:surgery / Q000662:veterinary*