title: Biomechanical performance of variable and fixed angle locked volar plates for the dorsally comminuted distal radius.
abstract: BACKGROUND
  The ideal treatment strategy for the dorsally comminuted distal radius fracture continues to evolve. Newer plate designs allow for variable axis screw placement while maintaining the advantages of locked technology. The purpose of this study is to compare the biomechanical properties of one variable axis plate with two traditional locked constructs.
  
  
  METHODS
  Simulated fractures were created via a distal 1 cm dorsal wedge osteotomy in radius bone analogs. The analogs were of low stiffness and rigidity to create a worst-case strength condition for the subject radius plates. This fracture-gap model was fixated using one of three different locked volar distal radius plates: a variable axis plate (Stryker VariAx) or fixed axis (DePuy DVR, Smith & Nephew Peri-Loc) designs. The constructs were then tested at physiologic loading levels in axial compression and bending (dorsal and volar) modes. Construct stiffness was assessed by fracture gap motion during the different loading conditions. As a within-study control, intact bone analogs were similarly tested.
  
  
  RESULTS
  All plated constructs were significantly less stiff than the intact control bone models in all loading modes (p<0.040). Amongst the plated constructs, the VariAx was stiffest axially (p=0.032) and the Peri-Loc was stiffest in bending (p<0.024).
  
  
  CONCLUSIONS
  In this analog bone fracture gap model, the variable axis locking technology was stiffer in axial compression than other plates, though less stiff in bending.
authors.affiliation: McLaren Regional Medical Center Flint, MI 48532.
authors.forename: D
authors.initials: D
authors.lastname: Martineau
authors.affiliation: William Beaumont Hospital Royal Oak, MI 48073.
authors.forename: J
authors.initials: J
authors.lastname: Shorez
authors.affiliation: McLaren Regional Medical Center Flint, MI 48532.
authors.forename: C
authors.initials: C
authors.lastname: Beran
authors.affiliation: McLaren Regional Medical Center Flint, MI 48532.
authors.forename: A G
authors.initials: AG
authors.lastname: Dass
authors.affiliation: McLaren Regional Medical Center Flint, MI 48532 ; Kettering University Flint, MI 48504.
authors.forename: P
authors.initials: P
authors.lastname: Atkinson
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D004867:Equipment Design; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008422:Materials Testing; D010027:Osteotomy / Q000295:instrumentation* / Q000379:methods; D053401:Palmar Plate; D011884:Radius / Q000601:surgery*; D011885:Radius Fractures / Q000601:surgery*