title: Stability of volar locking plate systems for AO type C3 fractures of the distal radius: biomechanical study in a cadaveric model.
abstract: BACKGROUND
  The purpose of the present study was to compare the relative stability of five volar locking plates (all of which are available for the treatment of intraarticular fractures of the distal radius) under loading conditions simulating the physiological forces that occur during early active mobilization.
  
  
  METHODS
  Five plating techniques were applied to surgically simulated AO type C3.2 distal radius fractures in formalin-fixed cadavers. The specimens were tested with a servohydraulic materials testing machine with 250 N of axial compression load for 3000 cycles. After cyclic loading, the specimens were loaded until they demonstrated failure in axial compression. The five fixation systems studied included a DRV locking plate (group 1), a Stellar plate (group 2), an Acu-Loc plate (group 3), AO Locking Distal Radius System 2.4 (group 4); and a Matrix SmartLock plate (group 5).
  
  
  RESULTS
  None of the plate fixations tested failed during the cyclic loading. Group 2 had a higher elastic limit than groups 4 and 5. There were no significant differences among the five groups for the failure load. Failure occurred at the distal portion of the fixation system, at the ulnar side locking pin, or the locking screw was bent (groups 1, 2, 3); the ulnar side locking screw was broken (groups 3, 4); the locking screw became loose (group 4); and the ulnar side locking screw was uncoupled from the screw hole (group 5).
  
  
  CONCLUSIONS
  All of the five volar plate fixation systems provided sufficient stability to permit 3000 repeated motions of the digits after surgery for AO type C3 distal radius fractures.
authors.affiliation: Department of Orthopaedic Surgery, Dokkyo Medical University School of Medicine, Shimotsuga-gun, Tochigi, Japan.
authors.forename: Shuzo
authors.initials: S
authors.lastname: Kamei
authors.forename: Denju
authors.initials: D
authors.lastname: Osada
authors.forename: Kazuya
authors.initials: K
authors.lastname: Tamai
authors.forename: Nakayuki
authors.initials: N
authors.lastname: Kato
authors.forename: Morimitsu
authors.initials: M
authors.lastname: Takai
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kameda
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Nohara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D002102:Cadaver; D019544:Equipment Failure Analysis; D006801:Humans; D057072:Intra-Articular Fractures / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011885:Radius Fractures / Q000601:surgery*; D016474:Weight-Bearing; D014955:Wrist Joint / Q000601:surgery*