title: Comparison of bone healing by demineralized bone matrix and autogenous cancellous bone in horses.
abstract: OBJECTIVE
  The purpose of this study was to compare bone healing induced by equine demineralized bone matrix (DBM) to autogenous cancellous bone graft (ACB) or no graft (control) in a rib-defect model in horses.
  
  
  METHODS
  The osteogenic properties of ACB and DBM were evaluated in bilateral 19-mm circular defects created in the outer cortex of the 6th and 8th ribs of each horse.
  
  
  METHODS
  Eight mature horses.
  
  
  METHODS
  Three rib defects in each horse were randomly treated with each of the 3 treatment groups, and the fourth rib defect received a random treatment. Rib sections, including the defects, were harvested 56 days after implantation and examined for bone mineral density, percent ash and calcium and graded for signs of radiographic and histological healing.
  
  
  RESULTS
  All ribs were fractured at the defect site and were classified as nonunion fractures 56 days after implantation. There were no significant differences among groups in bone mineral density and signs of radiographic or histological healing. There was an increased volume of bone in control and ACB-treated sites compared with DBM-treated sites. Rib defects treated with ACB were significantly higher in percent ash and calcium than those treated with DBM. DBM elicited no inflammatory reaction, and remodeling occurred around the periphery and within vascular channels of the decalcified particles.
  
  
  CONCLUSIONS
  DBM particles remodel from the periphery, which may explain the significantly lower percent ash, calcium, and bone when compared with ACB, because 2- to 4-microL pieces of DBM may act as space-occupying masses until completely mineralized. There was no evidence of enhanced healing associated with the use of DBM in this model.
  
  
  CONCLUSIONS
  Particles of 2 to 4 mm DBM should not be used as an aid to fracture repair because particles of this size interfere with normal mineralization. However, our model of nonunion fracture healing may be useful in future studies.
authors.affiliation: Department of Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins 80523, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Kawcak
authors.forename: G W
authors.initials: GW
authors.lastname: Trotter
authors.forename: B E
authors.initials: BE
authors.lastname: Powers
authors.forename: R D
authors.initials: RD
authors.lastname: Park
authors.forename: A S
authors.initials: AS
authors.lastname: Turner
mesh_terms: D000818:Animals; D016723:Bone Remodeling; D018786:Bone Substitutes; D016025:Bone Transplantation / Q000502:physiology / Q000662:veterinary*; D017102:Fracture Healing; D006736:Horses / Q000293:injuries* / Q000502:physiology*; D019637:Orthopedic Procedures / Q000662:veterinary; D010316:Particle Size; D012253:Rib Fractures / Q000503:physiopathology / Q000662:veterinary*
chemical_list: D018786:Bone Substitutes