title: [Biomechanical comparative study on proximal femoral locking plate and Gamma3 for treatment of stable intertrochanteric fracture].
abstract: OBJECTIVE
  To compare the biomechanical properties between the proximal femoral locking plate and Gamma3 for fixing stable intertrochanteric fracture so as to provide a theoretical basis for selecting internal fixation in the clinical application.
  
  
  METHODS
  Five pairs of antiseptic femur specimens were selected. Specimens of each pair of matching were randomly divided into groups A and B (n=5). All specimens were made the intertrochanteric fracture of 31A1.1 type according to AO/Association for the Study of Internal Fixation (AO/ASIF) classification. Fracture was fixed with Gamma3 in group A and with proximal femoral locking plate in group B. The axial compression, destruction, and torsion tests were carried out on the mechanical testing machine.
  
  
  RESULTS
  Axial compression test: The load-displacement curve of groups A and B was basically a straight line; axial stiffness of groups A and B was (621.00 ± 36.48) N/mm and (542.55 ± 46.94) N/mm respectively, showing significant difference (t = 3.648, P = 0.036). Destruction test: The maximum yield load of groups A and B was (4,394.82 ± 450.37) N and (2,987.54 ± 112.14) N respectively, showing significant difference (t = 5.433, P = -0.032). After loading maximum yield load, femoral fracture occurred again, and internal fixation and bone interface loosening were observed in group A; bending and breaking of proximal locking screw for internal fixation were found in group B, but loosening of internal fixation and bone interface was more obvious in group A than in group B. Torsion test: The torque of specimens in 2 groups increased with the increase of torsion angle (P < 0.05), the torque corresponding to the torsion angle in group B was larger than that in group A, but the difference was not significant (P > 0.05). The torsional stiffness of groups A and B was (1.78 ± 0.16) N·mm/deg and (2.01 ± 0.08) N·mm/deg respectively, showing no significant difference (t = -3.833, P = 0.162).
  
  
  CONCLUSIONS
  Proximal femoral locking plate and Gamma3 in the treatment of stable intertrochanteric fracture have good biomechanical properties, which can meet the requirements of minimal invasion, strong internal fixation, and early activity.
authors.forename: Wei
authors.initials: W
authors.lastname: Jiang
authors.forename: Yuehong
authors.initials: Y
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.forename: Shuping
authors.initials: S
authors.lastname: Liu
authors.forename: Desheng
authors.initials: D
authors.lastname: Zhang
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Hong
authors.initials: H
authors.lastname: Wang
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D005264:Femoral Fractures; D005269:Femur; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006620:Hip Fractures / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D019825:gamma-MSH
chemical_list: D019825:gamma-MSH