title: Biomechanical comparison of fixed-angle volar plate versus fixed-angle volar plate plus fragment-specific fixation in a cadaveric distal radius fracture model.
abstract: OBJECTIVE
  To test the hypothesis that combining orthogonal fragment-specific fixation with volar fixed-angle fixation provides markedly higher interfragment stability and construct strength compared with volar fixed-angle fixation alone.
  
  
  METHODS
  Eight matched pairs of fresh cadaveric hand and forearm specimens were potted upright in cement. Flexor and extensor tendons were isolated at insertion sites and sutured into a looped bundle for loading in flexion and extension, respectively (up to 61 N). Osteotomies to simulate an AO type C2, 3-part fracture pattern were created with a saw. One randomized specimen from each pair received a locking volar plate and a radial pin plate (VP+PP), and the other received a locking volar plate only (VP). The relative angular displacements between the radial, ulnar, and proximal fragments were obtained with a motion analysis system. After stability tests, specimens were compressed to failure in a wrist-extended position on a material testing machine. Paired t tests were used to compare the interfragment displacement, construct stiffness, and strength between the 2 groups.
  
  
  RESULTS
  Comparing fragment displacement in the VP+PP and VP groups showed that with flexion-extension and radial-ulnar deviation, distal fragment displacement was reduced to a statistically significant degree. The VP+PP group also showed higher failure strength and construct rigidity than the VP group.
  
  
  CONCLUSIONS
  In a simulated cadaveric model of the distal radius intra-articular fracture, the combined technique of fragment-specific plating with volar fixed-angle fixation alone provides superior biomechanical strength and stability over the volar fixed-angle fixation alone.
authors.affiliation: Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee, WI 53226-0099, USA. sgrindel@mcw.edu
authors.forename: Steven I
authors.initials: SI
authors.lastname: Grindel
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Matthew
authors.initials: M
authors.lastname: Gerlach
authors.forename: Linda M
authors.initials: LM
authors.lastname: McGrady
authors.forename: Susan
authors.initials: S
authors.lastname: Brown
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001860:Bone Plates; D002102:Cadaver; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D008422:Materials Testing; D008875:Middle Aged; D011474:Prosthesis Design; D011885:Radius Fractures / Q000503:physiopathology / Q000601:surgery*; D016474:Weight-Bearing / Q000502:physiology