title: Biomechanical Study of the Fixation Strength of Anteromedial Plating for Humeral Shaft Fractures.
abstract: BACKGROUND
  Open reduction and internal fixation with plate and screws are the gold standard for the surgical treatment of humeral shaft fractures, this study was to compare the mechanical properties of anteromedial, anterolateral, and posterior plating for humeral shaft fractures.
  
  
  METHODS
  A distal third humeral shaft fracture model was constructed using fourth-generation sawbones (#3404, composite bone). A total of 24 sawbones with a distal third humeral shaft fracture was randomly divided into three Groups: A, B, and C (n = 8 in each group) for anteromedial, anterolateral, and posterior plating, respectively. All sawbones were subjected to horizontal torsional fatigue tests, horizontal torsional and axial compressive fatigue tests, four-point bending fatigue tests in anteroposterior (AP) and mediolateral (ML) directions and horizontal torsional destructive tests.
  
  
  RESULTS
  In the horizontal torsional fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 6.12°, 6.53°, and 6.81°. In horizontal torsional and axial compressive fatigue tests, the mean torsional angle amplitude in Groups A, B, and C were 5.66°, 5.67°, and 6.36°. The mean plate displacement amplitude was 0.05 mm, 0.08 mm, and 0.10 mm. Group A was smaller than Group C (P < 0.05). In AP four-point bending fatigue tests, the mean plate displacement amplitude was 0.16 mm, 0.13 mm, and 0.20 mm. Group B was smaller than Group C (P < 0.05). In ML four-point bending fatigue tests, the mean plate displacement amplitude were 0.16 mm, 0.19 mm, and 0.17 mm. In horizontal torsional destructive tests, the mean torsional rigidity in Groups A, B, and C was 0.82, 0.75, and 0.76 N·m/deg. The yielding torsional angle was 24.50°, 25.70°, and 23.86°. The mean yielding torque was 18.46, 18.05, and 16.83 N·m, respectively.
  
  
  CONCLUSIONS
  Anteromedial plating was superior to anterolateral or posterior plating in all mechanical tests except in AP four-point bending fatigue tests compared to the anterolateral plating group. We can suggest that anteromedial plating is a clinically safe and effective way for humeral shaft fractures.
authors.affiliation: Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Yin-Feng
authors.initials: YF
authors.lastname: Zheng
authors.affiliation: Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Jun-Lin
authors.initials: JL
authors.lastname: Zhou
authors.affiliation: Technical Research Department, Beijing Medical Implant Engineering Research Center, Beijing 100095; Technical Research Department, Beijing Engineering Laboratory of Functional Medical Materials and Devices, Beijing 100095; Technical Research Department, Beijing Naton Technology Group Co., Ltd., Beijing 100095, China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shan
authors.affiliation: Department of Orthopedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D005593:Fracture Fixation, Internal; D006801:Humans; D006810:Humeral Fractures / Q000601:surgery*; D006811:Humerus / Q000601:surgery; D008953:Models, Anatomic; D013314:Stress, Mechanical