title: Biomechanical comparison of a locking compression plate combined with an intramedullary pin or a polyetheretherketone rod in a cadaveric canine tibia gap model.
abstract: OBJECTIVE
  To compare the biomechanical properties of a 10-hole 3.5 mm locking compression plate (LCP) with 2 proximal and 2 distal bicortical locked screws reinforced with either a Steinmann pin of 30-40% the medullary diameter or a poly-ether-ether-ketone (PEEK) rod of ∼75% the medullary diameter in a cadaveric tibia gap model.
  
  
  METHODS
  Ex vivo study.
  
  
  METHODS
  Cadaveric canine tibias (n = 8 pair).
  
  
  METHODS
  Each construct had a 10-hole 3.5 mm LCP with 2 screws per fracture fragment using a comminuted tibia gap model. The Steinmann pin constructs had a 2.4 mm intramedullary pin whereas the PEEK-rod constructs had a 6 mm intramedullary PEEK rod placed. Biomechanical testing included non-destructive bi-planar 4 point bending, torsion testing, and destructive axial compression. Testing produced the responses of failure load (N) in axial compression, stiffness (N/mm or N/°) in axial compression, torsion, lateral-medial, and caudal-cranial 4 point bending. Screw position within the PEEK-rods was determined after explantation.
  
  
  RESULTS
  The PEEK-rod constructs were significantly stiffer in axial compression (P < .005), lateral-medial 4 point bending (P < .001), and in torsional loading (P < .031) than the Steinman pin constructs. There was no significant difference between the constructs for stiffness in caudal-cranial 4 point bending (P = .32). The PEEK-rod constructs failed at a significantly higher load than the Steinmann pin constructs (P < .001). All constructs failed by yielding through plastic deformation. Each screw penetrated the PEEK rod in all constructs but the position of the screw varied.
  
  
  CONCLUSIONS
  PEEK-rod constructs failed at significantly higher loads and were significantly stiffer in 4 point lateral-medial bending, axial compression, and torsion when compared with Steinmann pin constructs.
authors.affiliation: School of Veterinary and Life Sciences, Murdoch University, Perth, Australia.
authors.forename: Lucas H
authors.initials: LH
authors.lastname: Beierer
authors.forename: Mark
authors.initials: M
authors.lastname: Glyde
authors.forename: Robert E
authors.initials: RE
authors.lastname: Day
authors.forename: Giselle L
authors.initials: GL
authors.lastname: Hosgood
mesh_terms: D000818:Animals; D001577:Benzophenones; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000662:veterinary*; D002102:Cadaver; D004285:Dogs / Q000601:surgery*; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000662:veterinary*; D006614:Hindlimb / Q000601:surgery; D007659:Ketones; D008297:Male; D008954:Models, Biological; D011092:Polyethylene Glycols; D011108:Polymers; D011474:Prosthesis Design; D013977:Tibia / Q000601:surgery*
chemical_list: D001577:Benzophenones; D007659:Ketones; D011108:Polymers; C063834:polyetheretherketone; D011092:Polyethylene Glycols