title: A biomechanical analysis of locking plate fixation with minimally invasive plate osteosynthesis in a subtrochanteric fracture model.
abstract: OBJECTIVE
  The objective of this study was to establish the relative fixation strengths of a locking plate, a dynamic condylar screw (DCS) plate, and a long proximal femoral nail (PFN).
  
  
  METHODS
  The study involved three groups of composite large femoral synthetic bones of five specimens per group; plating using a locking compression plate-distal femur (LCP-DF), plating using a DCS plate, and nailing using a long PFN. A gap osteotomy model was used to simulate a comminuted subtrochanteric femur fracture. For each femur, a minimal preload of 100 N was applied before loading to failure. A vertical load was applied at 10 mm/min until femur failure. Load to failure, mode of failure, and displacement at load to failure were documented.
  
  
  RESULTS
  Fixation strength (load or moment to failure) of LCP-DF (1,330 N; range, 1,217-1,460 N) was 26.6% and was greater in axial loading compared with DCS (1050.5 N; range, 956.4-1194.5 N) and 250% less in axial loading compared with long PFN (3633.1 N; range, 3337.2-4020.4 N; p=0.002). Ultimate displacement in axial loading was similar for LCP-DF (18.4 mm; standard deviation [SD], 1.44), DCS (18.3 mm; SD, 3.25), and long PFN (16.7 mm; SD, 1.82).
  
  
  CONCLUSIONS
  The LCP-DF construct proved stronger than the DCS in terms of ultimate strength by biomechanical testing of a simulated subtrochanteric femur fracture with comminution. Although the nail construct proved strongest, the biomechanical performance of the locking plate construct may lend credence to the use of a locking plate versus the DCS plate for minimally invasive plate osteosynthesis of subtrochanteric femur fractures, which may be technically difficult to fix using a nail.
authors.affiliation: Department of Orthopedic Surgery, Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Joon-Woo
authors.initials: JW
authors.lastname: Kim
authors.forename: Chang-Wug
authors.initials: CW
authors.lastname: Oh
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Byun
authors.forename: Jong-Keon
authors.initials: JK
authors.lastname: Oh
authors.forename: Hee-June
authors.initials: HJ
authors.lastname: Kim
authors.forename: Woo-Kie
authors.initials: WK
authors.lastname: Min
authors.forename: Sung-Ki
authors.initials: SK
authors.lastname: Park
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Park
mesh_terms: D001696:Biomechanical Phenomena / Q000502:physiology; D001858:Bone Nails; D001860:Bone Plates; D004868:Equipment Failure; D005269:Femur / Q000503:physiopathology / Q000601:surgery; D005593:Fracture Fixation, Internal / Q000379:methods*; D006620:Hip Fractures / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008953:Models, Anatomic; D008954:Models, Biological; D016474:Weight-Bearing / Q000502:physiology