title: Stability of radial head and neck fractures: a biomechanical study of six fixation constructs with consideration of three locking plates.
abstract: OBJECTIVE
  Open reduction and internal fixation of radial neck fractures can lead to secondary loss of reduction and nonunion due to insufficient stability. Nevertheless, there are only a few biomechanical studies about the stability achieved by different osteosynthesis constructs.
  
  
  METHODS
  Forty-eight formalin-fixed, human proximal radii were divided into 6 groups according to their bone density (measured by dual-energy x-ray absorptiometry). A 2.7-mm gap osteotomy was performed to simulate an unstable radial neck fracture, which was fixed with 3 nonlocking implants: a 2.4-mm T plate, a 2.4-mm blade plate, and 2.0-mm crossed screws, and 3 locking plates: a 2.0-mm LCP T plate, a 2.0-mm 6x2 grid plate, and a 2.0-mm radial head plate. Implants were tested under axial (N/mm) and torsional (Ncm/ degrees ) loads with a servohydraulic materials testing machine.
  
  
  RESULTS
  The radial head plate was significantly stiffer than all other implants under axial as well as under torsional loads, with values of 36 N/mm and 13 Ncm/ degrees . The second-stiffest implant was the blade plate, with values of 20 N/mm and 6 Ncm/ degrees . The weakest implants were the 2.0-mm LCP, with values of 6 N/mm and 2 Ncm/ degrees , and the 2.0-mm crossed screws, with values of 18 N/mm and 2 Ncm/ degrees . The 2.4-mm T plate, with values of 14 N/mm and 4 Ncm/ degrees , and the 2.0-mm grid plate, with values of 8 N/mm and 4 Ncm/ degrees came to lie in the midfield.
  
  
  CONCLUSIONS
  The 2.0-mm angle-stable plates-depending on their design-allow fixation with comparable or even higher stability than the bulky 2.4-mm nonlocking implants and 2.0-mm crossed screws.
authors: Department of Trauma Surgery, Johannes Gutenberg-University, Mainz, Germany.
authors: Klaus Josef
authors: KJ
authors: Burkhart
authors: Lars P
authors: LP
authors: Mueller
authors: David
authors: D
authors: Krezdorn
authors: Philipp
authors: P
authors: Appelmann
authors: Karl J
authors: KJ
authors: Prommersberger
authors: Werner
authors: W
authors: Sternstein
authors: Pol M
authors: PM
authors: Rommens
mesh_terms: D001860:Bone Plates; D002102:Cadaver; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D011474:Prosthesis Design; D011859:Radiography; D011885:Radius Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013314:Stress, Mechanical; D054159:Torsion, Mechanical