title: Biomechanical analysis of location of lag screw of a dynamic hip screw in treatment of unstable intertrochanteric fracture.
abstract: OBJECTIVE
  The aim of this study was to assess the most adequate location of a lag screw of a dynamic hip screw in the treatment of an unstable intertrochanteric fracture.
  
  
  METHODS
  Six pairs of proximal femora obtained from fresh adult cadavers were inflicted with iatrogenic unstable intertrochanteric fractures. Fractures of both sides were stabilized with two different favored locations of a lag screw and tested by a Material Testing System machine with increased loads to evaluate the relative migration of the femoral head.
  
  
  RESULTS
  There was significant difference (p < 0.05) with less migration of the femoral head by inferior insertion of a lag screw in the frontal plane and central insertion in the coronal plane.
  
  
  CONCLUSIONS
  Based on theoretical and experimental considerations, the most adequate location of a lag screw of a dynamic hip screw should be inferior in the frontal plane and central in the coronal plane.
authors.affiliation: Department of Orthopedics, Chang Gung Memorial Hospital, Taiwan, Republic of China.
authors.forename: C C
authors.initials: CC
authors.lastname: Wu
authors.forename: C H
authors.initials: CH
authors.lastname: Shih
authors.forename: M Y
authors.initials: MY
authors.lastname: Lee
authors.forename: C L
authors.initials: CL
authors.lastname: Tai
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D005548:Foreign-Body Migration; D005593:Fracture Fixation, Internal / Q000379:methods*; D006620:Hip Fractures / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged