title: Biomechanical Comparison of Two Kinds of Internal Fixation in a Type C Zone II Pelvic Fracture Model.
abstract: BACKGROUND
  Unstable pelvic fractures are complex and serious injuries. Selection of a fixation method for these fractures remains a challenging problem for orthopedic surgeons. This study aimed to compare the stability of Tile C pelvic fractures fixed with two iliosacral (IS) screws and minimally invasive adjustable plate (MIAP) combined with one IS screw.
  
  
  METHODS
  This study was a biomechanical experiment. Six embalmed specimens of the adult pelvis were used. The soft tissue was removed from the specimens, and the spines from the fourth lumbar vertebra to the proximal one-third of both femurs were retained. The pubic symphysis, bilateral sacroiliac joints and ligaments, bilateral hip joints, bilateral sacrotuberous ligaments, and bilateral sacrospinous ligaments were intact. Tile C pelvic fractures were made on the specimens. The symphysis pubis was fixed with a plate, and the fracture on the posterior pelvic ring was fixed with two kinds of internal fixation in turn. The specimens were placed in a biomechanical machine at a standing neutral posture. A cyclic vertical load of up to 500 N was applied, and displacement was recorded. Shifts in the fracture gap were measured by a grating displacement sensor.
  
  
  METHODS
  Paired-samples t-test.
  
  
  RESULTS
  Under the vertical load of 100, 200, 300, 400, and 500 N, the average displacement of the specimens fixed with MIAP combined with one IS screw was 0.46, 0.735, 1.377, 1.823, and 2.215 mm, respectively, which was significantly lower than that of specimens fixed with two IS screws under corresponding load (P < 0.05). Under the vertical load of 500 N, the shift in the fracture gap of specimens fixed with MIAP combined with one IS screw was 0.261 ± 0.095 mm, and that of specimens fixed with two IS screws was 0.809 ± 0.170 mm. The difference was significant (P < 0.05).
  
  
  CONCLUSIONS
  The stability of Tile C pelvic fractures fixed with MIAP combined with one IS screw was better than that fixed with two IS screws.
authors: Tao
authors: T
authors: Wu
authors: Wei
authors: W
authors: Chen
authors: Qi
authors: Q
authors: Zhang
authors: Zhan-Le
authors: ZL
authors: Zheng
authors: Hong-Zhi
authors: HZ
authors: Lyu
authors: Yun-Wei
authors: YW
authors: Cui
authors: Xiao-Dong
authors: XD
authors: Cheng
authors: Department of Orthopaedics, Third Hospital, Hebei Medical University, Shijiazhuang, Hebei 050051, China.
authors: Ying-Ze
authors: YZ
authors: Zhang
authors: Yan-Jiang
authors: YJ
authors: Yang
mesh_terms: D000328:Adult; D001863:Bone Screws; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000601:surgery*