title: [Finite element analysis of lumbar pelvic and proximal femur model with simulate lumbar rotatory manipulation].
abstract: OBJECTIVE
  To study the changes of displacement and stress in the model of lumbar pelvic and proximal femur during lumbar rotatory manipulation.
  
  
  METHODS
  The date of lumbar pelvic and proximal femur CT scan by Mimics 10.01 software was established a lumbar pelvic and proximal femur geometric model, then the model was modified with Geomagic 9, at last the modified model was imported into hypermesh 10 and meshed with tetrahedron, at the same time,add disc and ligaments. According to the principle of lumbar rotatory manipulation,the lumbar rotatory manipulation were decomposed. The mechanical parameters assigned into the three-dimensional finite element model. The changes of displacement and stress in the model of lunbar pelvic and proximal femur under the four conditions were calculated with Abaqus model of Hypermesh 10.
  
  
  RESULTS
  1) Under the same condition,the displacement order of lumbar was L1>L2>L3>L5 L5, anterior column > middle column > posterior column. 2) Under the different conditions, the displacement order of lumbar,case 3>case 1>case 4>case 2. 3) Under the same conditions, the displacement order of lumbar inter-vertebral disc from L1,2 to L5S1 was L1,2>L2,3>L3,4>L4,5>L5S1, as for the same inter-vertebral disc, the order was: second quadrant>third quadrant>first quadrant>fourth quadrant. 4) Under the different conditions,the displacement order of the inter-vertebral disc was L1,2>L2,3>L3,4>L4,5>L5S1, but to same inter-vertebral disc: case 3>case 4>case 1 >case 2. 5) There were apparent displacement and stress concentration in pelvis and hip during the manipulation.
  
  
  CONCLUSIONS
  1) The principles of lumbar rotation manipulation closely related to the relative displacement caused by rotation of various parts of lumbar pelvic and proximal femur model; 2) During the process of lumbar rotatory manipulation, the angle of lateral bending and flexion can not be randomly increased; 3) During the process of lumbar rotatory manipulation, all the conditions of lumbar pelvic and proximal femur must be considered to determine indications and contraindications.
authors.affiliation: Department of Orthopaedics, Hospital of Traditional Chinese Medicine of Hubei, Wuhan 430000, Hubei, China. huhuaonline@126.com
authors.forename: Hua
authors.initials: H
authors.lastname: Hu
authors.forename: Chang-Yuan
authors.initials: CY
authors.lastname: Xiong
authors.forename: Guo-Wu
authors.initials: GW
authors.lastname: Han
mesh_terms: D005269:Femur; D020342:Finite Element Analysis; D006801:Humans; D008159:Lumbar Vertebrae; D026201:Musculoskeletal Manipulations; D010388:Pelvis; D012399:Rotation