title: Biomechanical comparison of orthogonal versus parallel double plating systems in intraarticular distal humerus fractures.
abstract: OBJECTIVE
  In intraarticular distal humerus fractures, internal fixation with double plates is the gold standard treatment. However the optimal plate configuration is not clear in the literature. The aim of this study was to compare the biomechanical stability of the parallel and the orthogonal anatomical locking plating systems in intraarticular distal humerus fractures in artificial humerus models.
  
  
  METHODS
  Intraarticular distal humerus fracture (AO13-C2) with 5 mm metaphyseal defect was created in sixteen artificial humeral models. Models were fixed with either orthogonal or parallel plating systems with locking screws (Acumed elbow plating systems). Both systems were tested for their stiffness with loads in axial compression, varus, valgus, anterior and posterior bending. Then plastic deformation after cyclic loading in posterior bending and load to failure in posterior bending were tested. The failure mechanisms of all the samples were observed.
  
  
  RESULTS
  Stiffness values in every direction were not significantly different among the orthogonal and the parallel plating groups. There was no statistical difference between the two groups in plastic deformation values (0.31 mm-0.29 mm) and load to failure tests in posterior bending (372.4 N-379.7 N). In the orthogonal plating system most of the failures occurred due to the proximal shaft fracture, whereas in the parallel plating system failure occurred due to the shift of the most distal screw in proximal fragment.
  
  
  CONCLUSIONS
  Our study showed that both plating systems had similar biomechanical stabilities when anatomic plates with distal locking screws were used in intraarticular distal humerus fractures in artificial humerus models.
authors.affiliation: Istanbul University, Istanbul Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: atalar.ac@gmail.com.
authors.forename: Ata C
authors.initials: AC
authors.lastname: Atalar
authors.affiliation: Istanbul University, Istanbul Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: dronurtunali@gmail.com.
authors.forename: Onur
authors.initials: O
authors.lastname: Tunalı
authors.affiliation: Istanbul University, Istanbul Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: ali_ersen@hotmail.com.
authors.forename: Ali
authors.initials: A
authors.lastname: Erşen
authors.affiliation: Istanbul University, Istanbul Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: mkapicioglu@yahoo.com.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Kapıcıoğlu
authors.affiliation: Istanbul University, Istanbul Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: yavuz_saglam@hotmail.com.
authors.forename: Yavuz
authors.initials: Y
authors.lastname: Sağlam
authors.affiliation: Koç University, Medical Faculty Orthopaedics and Traumatology Department, Istanbul, Turkey. Electronic address: mdemirhan@ku.edu.tr.
authors.forename: Mehmet S
authors.initials: MS
authors.lastname: Demirhan
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D006801:Humans; D006810:Humeral Fractures / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D006811:Humerus / Q000293:injuries / Q000601:surgery; D057072:Intra-Articular Fractures / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery; D008422:Materials Testing / Q000379:methods; D008953:Models, Anatomic; D011859:Radiography / Q000379:methods
keywords: Biomechanic; Distal humerus fracture; Orthogonal plating; Parallel plating