title: [Biomechanical study of new type two-head automatic pressure external fixator (TAPEF) for the treatment of intertrochanteric fracture].
abstract: OBJECTIVE
  To investigate the mechanical characteristics of new type two-head automatic pressure external fixator in the view of biomechanics.
  
  
  METHODS
  Fifteen fresh and humid specimens were selected and divided into experimental group (5 cases) and control group (10 cases). The control group were respectively applied with DHS (5 cases) and traditional external fixator (5 cases). In order to compare the different apparatus, the strength, stiffness and twist mechanical function of femoral intertrochanteric fracture with different device were measured respectively when the specimens were under the pressure of 0-1800 N and loading speed 1.4 mn/min.
  
  
  RESULTS
  The strength, stiffness, twist mechanical function and maximum endurance of femora in the experimental group were obviously superior than that of DHS and traditional external fixator (P < 0.05).
  
  
  CONCLUSIONS
  Two head automatic new type pressure external fixator can embed more tightly without sliding, also can prevent the occurrence of coxa vara effectively.
authors.affiliation: Department of Orthopaedics, Danyang TCM Hospital, Danyang 212300, Jiangsu, China. qinyx9692@163.com
authors.forename: Yu-xing
authors.initials: YX
authors.lastname: Qin
authors.forename: Guo-qing
authors.initials: GQ
authors.lastname: Sheng
authors.forename: Yi-jin
authors.initials: YJ
authors.lastname: Wang
authors.forename: Lin-zhong
authors.initials: LZ
authors.lastname: Jiang
authors.forename: Yun-wei
authors.initials: YW
authors.lastname: Mao
authors.forename: Rong-jun
authors.initials: RJ
authors.lastname: Shi
authors.forename: Jun-chao
authors.initials: JC
authors.lastname: Shu
mesh_terms: D016267:External Fixators; D005264:Femoral Fractures / Q000601:surgery*; D005592:Fracture Fixation / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D013314:Stress, Mechanical