title: A technique for creating critical-size defects in the metatarsus of sheep for use in investigation of healing of long-bone defects.
abstract: OBJECTIVE
  To develop a technique for use in investigation of healing of long-bone defects by creation of a critical-size defect in the left metarsal III and IV bone (metatarsus) of sheep.
  
  
  METHODS
  18 healthy adult sheep.
  
  
  METHODS
  Sheep were allocated to 4 groups (3, 3, 5, and 7 sheep in groups 1 to 4, respectively). An ostectomy with various segmental length-to-diaphyseal diameter ratios (0.5, 1.0, 2.0, and 2.0 for groups 1 to 4, respectively) was performed on the left metatarsus of each sheep. The defect was left empty in sheep of groups 1, 2, and 3, whereas the defect was filled with a massive corticocancellous bone autograft in sheep of group 4.
  
  
  RESULTS
  All sheep tolerated the surgical procedure well and were able to use the affected limb the day after surgery. Radiographic and histologic examinations conducted 16 weeks after surgery revealed nonunion in all sheep of groups 1, 2, and 3, whereas consistent bone healing with abundant bone formation was observed in all sheep of group 4.
  
  
  CONCLUSIONS
  Analysis of these findings suggests that the sheep metatarsal model is a critical-size defect model with low morbidity. It should allow the assessment of new technologies for bone regeneration in conditions closely mimicking the clinical setting.
  
  
  CONCLUSIONS
  Use of this technique in sheep should be of benefit for the preclinical study of osteoconductive, osteoinductive, or osteogenic biomaterials for use in humans.
authors.affiliation: Laboratoire de Recherches Orthopédiques, Centre National de la Recherche Scientifique-Sciences pour l'Ingénieur, Faculté de Médecine Lariboisière Saint-Louis, Université Denis Diderot, Paris, France
authors.forename: Véronique
authors.initials: V
authors.lastname: Viateau
authors.forename: Geneviève
authors.initials: G
authors.lastname: Guillemin
authors.forename: Yu Chien
authors.initials: YC
authors.lastname: Yang
authors.forename: Wassila
authors.initials: W
authors.lastname: Bensaid
authors.forename: Thierry
authors.initials: T
authors.lastname: Reviron
authors.forename: Karim
authors.initials: K
authors.lastname: Oudina
authors.forename: Alain
authors.initials: A
authors.lastname: Meunier
authors.forename: Laurent
authors.initials: L
authors.lastname: Sedel
authors.forename: Hervé
authors.initials: H
authors.lastname: Petite
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000502:physiology*; D018483:Diaphyses / Q000503:physiopathology / Q000601:surgery*; D004195:Disease Models, Animal; D005260:Female; D017102:Fracture Healing / Q000502:physiology*; D008682:Metatarsal Bones / Q000000981:diagnostic imaging / Q000502:physiology*; D008684:Metatarsus / Q000000981:diagnostic imaging / Q000293:injuries*; D008852:Microradiography / Q000662:veterinary; D012756:Sheep / Q000293:injuries* / Q000502:physiology; D013522:Surgery, Veterinary / Q000379:methods