title: Evaluation of a Novel Screw Position in a Type III Distal Phalanx Fracture Model: An Ex Vivo Study.
abstract: OBJECTIVE
  Mechanical evaluation of a novel screw position used for repair in a type III distal phalanx fracture model and assessment of solar canal penetration (SCP).
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  Disarticulated equine hooves (n = 24) and 24 isolated distal phalanges.
  
  
  METHODS
  Hooves/distal phalanges cut in a sagittal plane were repaired with 1 of 2 different cortical screw placements in lag fashion. In group 1 (conventional screw placement), the screw was inserted halfway between the proximal border of the solar canal (SC) and the subchondral bone surface on a line parallel to the dorsal cortex, whereas in group 2, the screw was inserted more palmar/plantar, where a perpendicular line drawn from the group 1 position reached the palmar/plantar cortex. Construct strength was evaluated by 3-point bending to failure. SCP was assessed by CT imaging and macroscopically.
  
  
  RESULTS
  Screws were significantly longer in group 2 and in forelimbs. Group 2 isolated distal phalanges had a significantly more rigid fixation compared with the conventional screw position (maximum point at failure 31%, bending stiffness 41% higher). Lumen reduction of the SC was observed in 13/52 specimens (all from group 2), of which 9 were forelimbs.
  
  
  CONCLUSIONS
  More distal screw positioning compared with the conventionally recommended screw position for internal fixation of type III distal phalangeal fractures allows placement of a longer screw and renders a more rigid fracture fixation. The novel screw position, however, carries a higher risk of SCP.
authors.affiliation: ISME Equine Hospital, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Dorian
authors.initials: D
authors.lastname: Bindler
authors.affiliation: ISME Equine Hospital, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Koch
authors.affiliation: Department of Clinical Veterinary Medicine, Clinical Radiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
authors.forename: Karine
authors.initials: K
authors.lastname: Gendron
authors.affiliation: Institute for Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland.|ETH Zurich, Institute for Biomechanics, Zurich, Switzerland.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Ferguson
authors.affiliation: Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.
authors.forename: Andras D
authors.initials: AD
authors.lastname: Kaposi
authors.affiliation: Department of Orthopaedics and Surgery, University of Miskolc, Miskolc, Hungary.
authors.forename: Miklos
authors.initials: M
authors.lastname: Papp
authors.affiliation: ISME Equine Hospital, Vetsuisse Faculty, University of Bern, Bern, Switzerland.|Equine Department and Clinic, Faculty of Veterinary Science Budapest, Szent István University, Üllő, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Bodó
mesh_terms: D000818:Animals; D001863:Bone Screws / Q000662:veterinary*; D002102:Cadaver; D005552:Forelimb / Q000601:surgery; D050723:Fractures, Bone / Q000601:surgery / Q000662:veterinary*; D006614:Hindlimb / Q000601:surgery; D006736:Horses / Q000293:injuries / Q000601:surgery*; D050277:Toe Phalanges / Q000601:surgery