title: Intramedullary nailing vs. palmar locked plating for unstable dorsally comminuted distal radius fractures: a biomechanical study.
abstract: BACKGROUND
  The purpose of this study was to compare the stability of a 2.4mm palmar locking compression plate and a new intramedullary nail-plate-hybrid Targon DR for dorsally comminuted distal radius fractures.
  
  
  METHODS
  An extraarticular 10mm dorsally open wedge osteotomy was created in 8 pairs of fresh frozen human radii to simulate an AO-A3-fracture. The fractures were stabilized using one of the fixation methods. The specimens were loaded axially with 200 N and dorsal-excentrically with 80 N. 2000cycles of dynamic loading and axial loading-to-failure were performed.
  
  
  RESULTS
  Axial loading revealed that intramedullary osteosynthesis (Targon DR: 369 N/mm) was significantly (p=0.017) stiffer than plate osteosynthesis (Locking compression plate: 131 N/mm). With 214 N/mm the intramedullary nail also showed higher stability during dorsal excentric loading than the Locking compression plate with 51 N/mm (p=0.012). After 2000 cycles of axial loading with 80 N the Targon DR-group was significantly stiffer than the Locking compression plate-group under both loading patterns. Neither group showed significant changes in stiffness after 2000 cycles. Under dorsal excentric loading the Targon DR-group was still significantly stiffer with 212 N/mm than the Locking compression plate-group with 45 N/mm (p=0.012). The load to failure tests demonstrated higher stability of intramedullary nailing (625 N) when compared to plate osteosynthesis (403 N) (p<0.025).
  
  
  CONCLUSIONS
  The study shows that intramedullary fixation of a distal AO-A3 radial fracture is biomechanically more stable than volar fixed-angle plating under axial and dorsal-excentric loading in an experimental setup.
authors.affiliation: Department of Trauma Surgery, Center for Musculoskeletal Surgery, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstrasse 1, 55131 Mainz, Germany.
authors.forename: Klaus J
authors.initials: KJ
authors.lastname: Burkhart
authors.forename: Tobias E
authors.initials: TE
authors.lastname: Nowak
authors.forename: Georg
authors.initials: G
authors.lastname: Gradl
authors.forename: Daniela
authors.initials: D
authors.lastname: Klitscher
authors.forename: Isabella
authors.initials: I
authors.lastname: Mehling
authors.forename: Dorothea
authors.initials: D
authors.lastname: Mehler
authors.forename: Lars P
authors.initials: LP
authors.lastname: Mueller
authors.forename: Pol M
authors.initials: PM
authors.lastname: Rommens
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D005593:Fracture Fixation, Internal; D005594:Fracture Fixation, Intramedullary; D018460:Fractures, Comminuted / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D011885:Radius Fractures / Q000503:physiopathology / Q000601:surgery*