title: Conversion of external fixation to definitive intramedullary nailing in experimental tibial fractures.
abstract: OBJECTIVE
  Initial treatment with external fixation of tibial fractures is indicated in severely injuried multitrauma patients. A conversion procedure to secondary nailing is often performed later to enhance fracture repair. The aim of the study was to compare definitive treatment of experimental tibial fractures with external fixation to an early conversion to secondary intramedullary nailing with large and small diameter nails.
  
  
  METHODS
  Thirty male rats were subject to a standardized tibial shaft osteotomy initially stabilized with external fixation. On day 7, they were assigned to either the control group (group A, N = 10) or conversion to secondary nailing with a small (group B, N = 10) or large diameter nails (group C, N = 10). Evaluation at 60 days included radiography, dual energy radiographic absorptiometry (DXA), and mechanical bending testing.
  
  
  RESULTS
  All fractures healed radiographically with bridging of the fracture line and more or less visible periosteal callus formation. Group B demonstrated significantly increased mineralization and callus formation measured as DXA parameters, bone mineral content (BMC), and callus area (CA) compared to both the other two groups. This group also tended to have mechanically stronger bones with higher fracture energy compared to both the other two groups, but no significant difference in mechanical prioperties between the groups was found in our study.
  
  
  CONCLUSIONS
  In conclusion, we found that conversion from external fixation of leg fractures in rats to intramedullary nailing did not improve bone healing significantly supporting external fixation as definitive fracture management.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, University of Oslo, Norway and Institute of Surgical Research, Oslo University Hospital Rikshospitalet, Norway. u.sigurdsen@medisin.uio.no
authors.forename: Ulf
authors.initials: U
authors.lastname: Sigurdsen
authors.forename: Olav
authors.initials: O
authors.lastname: Reikeras
authors.forename: Stein Erik
authors.initials: SE
authors.lastname: Utvag
mesh_terms: D015502:Absorptiometry, Photon; D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000502:physiology; D001858:Bone Nails; D002146:Bony Callus / Q000000981:diagnostic imaging / Q000503:physiopathology; D016267:External Fixators; D017102:Fracture Healing / Q000502:physiology; D008297:Male; D023421:Models, Animal; D051381:Rats; D017208:Rats, Wistar; D013978:Tibial Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome