title: Comparison of hydroxyapatite-coated and uncoated pins for transfixation casting in horses.
abstract: OBJECTIVE
  To determine the extent to which a hydroxyapatite coating promotes pin stability in the third metacarpal bone during transfixation casting in horses.
  
  
  METHODS
  14 adult horses.
  
  
  METHODS
  7 horses each were assigned to either an uncoated or hydroxyapatite-coated pin group. Three transcortical pins were placed in the third metacarpal bone of each horse and incorporated into a cast for 8 weeks. Insertion and extraction torque were measured, and torque reduction was calculated. Radiography was performed at 0, 4, and 8 weeks. Lameness evaluation was performed at 2, 4, 6, and 8 weeks. Bacteriologic culture of pins and pin holes was performed at pin removal.
  
  
  RESULTS
  All horses used casts without major complication throughout the study. Insertion torque was higher in uncoated pins. There was no effect of group on extraction torque. Hydroxyapatite-coated pins had lower torque reduction. Five of 15 hydroxyapatite-coated pins maintained or increased stability, whereas all uncoated pins loosened. Pin hole radiolucency, lameness grades, and positive bacteriologic culture rates were not different between groups.
  
  
  CONCLUSIONS
  Hydroxyapatite coating increased pin stability within the third metacarpal bone of horses during 8 weeks of transfixation casting but did not improve pin performance on clinical assessments. Clinical use of hydroxyapatite-coated transfixation pins may result in greater pin stability; however, further research is necessary to improve the consistency of pin osteointegration and elucidate whether clinical benefits will ultimately result from this approach in horses.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA. tlescun@purdue.edu
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Lescun
authors.forename: Debra K
authors.initials: DK
authors.lastname: Baird
authors.forename: Laurinda J
authors.initials: LJ
authors.lastname: Oliver
authors.forename: Stephen B
authors.initials: SB
authors.lastname: Adams
authors.forename: Jan F
authors.initials: JF
authors.lastname: Hawkins
authors.forename: George E
authors.initials: GE
authors.lastname: Moore
mesh_terms: D000818:Animals; D001858:Bone Nails / Q000662:veterinary; D002370:Casts, Surgical / Q000662:veterinary; D020099:Coated Materials, Biocompatible / Q000627:therapeutic use*; D016267:External Fixators / Q000662:veterinary; D005592:Fracture Fixation / Q000662:veterinary; D017102:Fracture Healing; D006736:Horses / Q000293:injuries / Q000601:surgery*; D006882:Hydroxyapatites / Q000627:therapeutic use*; D008297:Male; D050279:Metacarpal Bones / Q000293:injuries / Q000601:surgery*; D016896:Treatment Outcome
chemical_list: D020099:Coated Materials, Biocompatible; D006882:Hydroxyapatites