title: Comparison of holding power of three different pin designs for external skeletal fixation in avian bone: a study in common buzzard (Buteo buteo).
abstract: OBJECTIVE
  (1) To evaluate resistance to axial extraction of 3 pin designs in avian humerus and tibiotarsus; (2) to assess the effect of pin location within the bone on holding power; and (3) to assess the influence of thread pitch on holding power.
  
  
  METHODS
  Resistance of pins to axial extraction was measured immediately after insertion.
  
  
  METHODS
  Adult common buzzards (Buteo buteo; n=9).
  
  
  METHODS
  Different pin designs (1 smooth; 2 threaded pins, differing in pitch) were inserted into the proximal and distal metaphysis and the proximal, middle, and distal diaphysis of the humerus and tibiotarsus. Maximum force required for axial extraction of pins was recorded.
  
  
  RESULTS
  Smooth pins had the lowest extraction force (P<.05). Pins inserted into the diaphysis (proximal, middle and distal) of the humerus and the distal metaphysis of the tibiotarsus had a greater pullout strength than pins in other locations. Pins with a smaller pitch inserted into the proximal diaphysis and distal metaphysis of the humerus, and the proximal metaphysis of the tibiotarsus had significantly greater holding power than pins with a larger pitch (P<.05).
  
  
  CONCLUSIONS
  Pins inserted into the diaphysis of humerus and the distal metaphysis of the tibiotarsus are better at resisting extraction. Pins with a smaller pitch possess greater holding power than pins with a larger pitch in avian humerus and tibiotarsus.
  
  
  CONCLUSIONS
  Consideration should be given to pin location and thread pitch, when choosing external skeletal fixation to repair an avian humeral or tibiotarsal fracture.
authors.affiliation: Department of Clinical Sciences, Lugo Veterinary College, University of Santiago de Compostela, Lugo, Spain. evacaspe1@hotmail.com
authors.forename: Eva
authors.initials: E
authors.lastname: Castiñeiras Pérez
authors.forename: Marcos
authors.initials: M
authors.lastname: Segade Seoane
authors.forename: Blanca
authors.initials: B
authors.lastname: Villanueva Santamarina
authors.forename: Antonio
authors.initials: A
authors.lastname: González Cantalapiedra
mesh_terms: D000818:Animals; D000835:Animals, Wild; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000662:veterinary*; D018483:Diaphyses / Q000601:surgery; D016267:External Fixators / Q000662:veterinary*; D046093:Falconiformes / Q000293:injuries* / Q000601:surgery; D005592:Fracture Fixation / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D050723:Fractures, Bone / Q000601:surgery / Q000662:veterinary*; D006811:Humerus / Q000601:surgery