title: Construction of Finite Element Model for an Artificial Atlanto-Odontoid Joint Replacement and Analysis of Its Biomechanical Properties.
abstract: OBJECTIVE
  To investigate the stress distribution on artificial atlantoaxial-odontoid joint (AAOJ) components during flexion, extension, lateral bending and rotation of AAOJ model constructed with the finite element (FE) method.
  
  
  METHODS
  Human cadaver specimens of normal AAOJ were CT scanned with 1 mm -thickness and transferred into Mimics software to reconstruct the three-dimensional models of AAOJ. These data were imported into Freeform software to place a AAOJ into a atlantoaxial model. With Ansys software, a geometric model of AAOJ was built. Perpendicular downward pressure of 40 N was applied to simulate gravity of a skull, then 1.53 N• m torque was exerted separately to simulate the range of motion of the model.
  
  
  RESULTS
  An FE model of atlantoaxial joint after AAOJ replacement was constructed with a total of 103 053 units and 26 324 nodes. In flexion, extension, right lateral bending and right rotation, the AAOJ displacement was 1.109 mm, 3.31 mm, 0.528 mm, and 9.678 mm, respectively, and the range of motion was 1.6°, 5.1°, 4.6° and 22°.
  
  
  CONCLUSIONS
  During all ROM, stress distribution of atlas-axis changed after AAOJ replacement indicating that AAOJ can offload stress. The stress distribution in the AAOJ can be successfully analyzed with the FE method.
authors.affiliation: The Affiliated Ningbo No.6 Hospital of Medical School of Ningbo University, Department of Spinal Surgery, Ningbo, Zhejiang Province, China.
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.forename: Wei-Xin
authors.initials: WX
authors.lastname: Dong
authors.forename: Shannon
authors.initials: S
authors.lastname: Hann
authors.forename: Zhen-Shan
authors.initials: ZS
authors.lastname: Yuan
authors.forename: Xiao-Yang
authors.initials: XY
authors.lastname: Sun
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.forename: Meichao
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000328:Adult; D001178:Arthroplasty; D019643:Arthroplasty, Replacement / Q000379:methods*; D001268:Atlanto-Axial Joint / Q000033:anatomy & histology* / Q000601:surgery*; D001696:Biomechanical Phenomena; D002102:Cadaver; D001270:Cervical Atlas / Q000033:anatomy & histology; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008022:Ligaments / Q000033:anatomy & histology; D008297:Male; D008953:Models, Anatomic; D009809:Odontoid Process / Q000033:anatomy & histology* / Q000601:surgery*; D016059:Range of Motion, Articular; D012886:Skull / Q000033:anatomy & histology; D013314:Stress, Mechanical