title: Vascularized bone grafting in a canine carpal avascular necrosis model.
abstract: BACKGROUND
  Limited experimental research has been performed on the treatment of avascular necrosis (AVN) by vascularized bone grafting.
  
  
  OBJECTIVE
  A new model simulating carpal AVN was created to investigate surgical revascularization of necrotic bone.
  
  
  METHODS
  In seven mongrel dogs, AVN was induced by removal of the radial carpal bones bilaterally, deep-freezing, coating in cyanoacrylate, and reimplantation. A reverse-flow vascularized bone graft from the distal radius was implanted in the avascular radial carpal bone. The contralateral side served as an untreated ischemic control. Bone blood flow, bone volume, radiography, histomorphometry, histology, and MRI were analyzed at 4 weeks.
  
  
  RESULTS
  Blood flow was substantially higher in grafted bones when compared with controls (14.68 ± 15.43 versus 0.27 ± 0.28 mL/minute/100 g). Blood flow correlated with increased osteoid formation and higher levels of bone turnover. T1 and T2 signals on MRI did not correlate with quantitative bone blood flow measurements. Necrotic bones with no blood flow had normal T1 and T2 signals, whereas revascularized bones had signal changes when compared with adjacent carpal bones. No major collapse occurred in any radiocarpal bone.
  
  
  CONCLUSIONS
  In a canine experimental model, investigation of carpal AVN shows the ability of vascularized bone grafting to revascularize and remodel avascular bone.
  
  
  CONCLUSIONS
  Surgical revascularization of necrotic bone induced by vascularized bone grafting results in increased bone perfusion and bone remodeling as compared with untreated necrotic bone. MRI T1 and T2 signals can be normal in necrotic avascular bone.
authors.affiliation: Department of Orthopedics, Orthopedic Research, Microvascular Research Laboratory, Mayo Clinic, 200 First Street, SW, Rochester, MN 55905, USA.
authors.forename: Wouter F
authors.initials: WF
authors.lastname: Willems
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Alberton
authors.forename: Allen T
authors.initials: AT
authors.lastname: Bishop
authors.forename: Thomas
authors.initials: T
authors.lastname: Kremer
mesh_terms: D000818:Animals; D016723:Bone Remodeling; D016025:Bone Transplantation; D002348:Carpal Bones / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D004285:Dogs; D008279:Magnetic Resonance Imaging; D008297:Male; D009929:Organ Size; D010020:Osteonecrosis / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D011859:Radiography; D011884:Radius / Q000098:blood supply* / Q000000981:diagnostic imaging / Q000637:transplantation*; D012039:Regional Blood Flow; D013997:Time Factors; D014182:Transplantation, Autologous