Hybrid plating shows equivalent biomechanical bending strength to unicortical locked plating

Jeremy S. Somerson, Jake P. Heiney, Suneel Battula, Andrew J. Schoenfeld

Research output: Contribution to journalArticlepeer-review


Locking unicortical screw fixation of diaphyseal fractures may be clinically necessary due to internal constructs or prosthetic implants. The biomechanical effects of substituting one or more bicortical nonlocking screws to create a "hybrid" construct are unknown. Use of an initial nonlocking screw may be clinically desirable for creating initial plate-to-bone fixation prior to locking. A validated transverse fracture model was used with eighteen synthetic humerus models. Plate and screw fixation was performed in three treatment groups (n = 6): Unicortical locking screws only, fixation with two unicortical locking screws and one bicortical nonlocking screw on either side of the fracture and fixation with one unicortical locking screw and two bicortical locking screws on either side of the fracture. Displacement and gap strain measurements were made with a cyclic 4-point bending test. No significant differences were noted for construct stiffness or gap micromotion among the three groups on cyclic testing. Measurements at 1000, 5000, and 10,000 cycles showed stable fixation of all construct types with no significant changes in stiffness or micromotion. Substitution of one or more bicortical nonlocking screws in a unicortical locked construct does not affect construct stiffness or fracture gap strain. Data proven through controlled laboratory study.

Original languageEnglish (US)
Article number1450071
JournalJournal of Mechanics in Medicine and Biology
Issue number5
StatePublished - Oct 2014
Externally publishedYes


  • Biomechanical
  • fixed angle
  • hybrid plating
  • locking plate
  • unicortical

ASJC Scopus subject areas

  • Biomedical Engineering


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