title: Calcium phosphate cement augmentation after volar locking plating of distal radius fracture significantly increases stability.
abstract: OBJECTIVE
  Distal radius fractures represent the most common fractures in adults. Volar locking plating to correct unstable fractures has become increasingly popular. Although reasonable primary reduction is possible in most cases, maintenance of reduction until the fracture is healed is often problematic in osteoporotic bone. To our knowledge, no biomechanical studies have compared the effect of enhancement with biomaterial on two different volar fixed-angle plates.
  
  
  METHODS
  Human fresh-frozen cadaver pairs of radii were used to simulate an AO/OTA 23-A3 fracture. In a total of four groups (n = 7 for each group), two volar fixed-angle plates (Aptus 2.5 mm locking fracture plate, Medartis, Switzerland and VA-LCP two-column distal radius plate 2.4, volar, Synthes, Switzerland) with or without an additional injection of a biomaterial (Hydroset Injectable HA Bone Substitute, Stryker, Switzerland) into the dorsal comminution zone were used to fix the distal metaphyseal fragment. Each specimen was tested load-controlled under cyclic loading with a servo-hydraulic material testing machine. Displacement, stiffness, dissipated work and failure mode were recorded.
  
  
  RESULTS
  Improved mechanical properties (decreased displacement, increased stiffness, decreased dissipated work) were found in both plates if the biomaterial was additionally injected. Improvement of mechanical parameters after biomaterial injection was more evident in the Synthes plate compared to the Aptus plate. Pushing out of the screws was noticed as a failure mode only in samples lacking supplementary biomaterial.
  
  
  CONCLUSIONS
  Injection of a biomaterial into the dorsal comminution zone increases stability after volar locking plating of distal radius fractures in vitro.
authors.affiliation: Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Donaueschingenstraße 13, 1200, Vienna, Austria.
authors.forename: Hans
authors.initials: H
authors.lastname: Kainz
authors.forename: Enrico
authors.initials: E
authors.lastname: Dall'Ara
authors.forename: Anna
authors.initials: A
authors.lastname: Antoni
authors.forename: Heinz
authors.initials: H
authors.lastname: Redl
authors.forename: Philippe
authors.initials: P
authors.lastname: Zysset
authors.forename: Patrick
authors.initials: P
authors.lastname: Weninger
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001843:Bone Cements / Q000627:therapeutic use*; D001860:Bone Plates; D018786:Bone Substitutes / Q000627:therapeutic use*; D002102:Cadaver; D002130:Calcium Phosphates / Q000627:therapeutic use*; D006801:Humans; D011885:Radius Fractures / Q000601:surgery*
chemical_list: D001843:Bone Cements; D018786:Bone Substitutes; D002130:Calcium Phosphates; C020243:calcium phosphate
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