title: [An improved liquid nitrogen freezing method for establishing canine models of femoral head necrosis].
abstract: OBJECTIVE
  To establish an canine model of femoral head osteonecrosis using an improved liquid nitrogen freezing method.
  
  
  METHODS
  Sixteen adult canines were divided into 4 groups at random and subjected to instant freezing of the unilateral femoral head with liquid nitrogen. The dogs were observed at 2, 4, 8, and 16 weeks after the operation for radiographic, gross and pathological changes of the femoral head.
  
  
  RESULTS
  Significant radiographic, gross and pathological changes occurred in the femoral head after the freezing.
  
  
  CONCLUSIONS
  Improved liquid nitrogen freezing of the femoral head provides a simple and convenient method for establishing animal models of femoral head osteonecrosis.
authors.affiliation: Department of Orthopedics, Tangdu Hospital, Fourth Military Medical University, Xi'an 710038, China.
authors.forename: Guo-zhu
authors.initials: GZ
authors.lastname: Liu
authors.forename: Tong-tao
authors.initials: TT
authors.lastname: Yang
authors.forename: Jian-wei
authors.initials: JW
authors.lastname: Han
authors.forename: Jin
authors.initials: J
authors.lastname: Wu
authors.forename: Yan-hua
authors.initials: YH
authors.lastname: Wen
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.forename: Bao-an
authors.initials: BA
authors.lastname: Ma
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D005260:Female; D005271:Femur Head Necrosis; D005615:Freezing; D008297:Male; D009584:Nitrogen / Q000737:chemistry*
chemical_list: D009584:Nitrogen