Biomechanical comparison of locked versus non-locked symphyseal plating of unstable pelvic ring injuries

  • R. J. Godinsky
  • G. A. Vrabec
  • L. M. Guseila
  • D. E. Filipkowski
  • J. J. Elias
Original Article



Locked symphyseal plates are utilized to provide higher levels of construct stiffness than non-locked plates. The current biomechanical study was performed to compare stiffness at the pubic symphysis between locked and non-locked plating systems.


Synthetic models were utilized to represent injury to the pelvis and symphyseal plating combined with a sacro-iliac screw. Seven models were evaluated with plates and locking screws, and seven were evaluated with non-locking screws. Single limb stance was simulated, with all models loaded for 1000 cycles with 350 N applied at the sacrum. Two pairs of markers crossing the symphysis were tracked with a video-based tracking system. A coordinate system was developed to quantify motion between the pairs in three directions: medial–lateral gap, anterior–posterior shear translation, and superior–inferior shear translation. Significant differences between the plating systems were identified with t tests (p < 0.05).


Anterior–posterior shear translation varied significantly between the two plating systems. From cycles 100 to 1000, average shear translation for the non-locked and locked systems was ~0.7 and 0.3 mm, respectively, at the markers closest to the plate and 2.2 and 1.4 mm, respectively, at the markers further from the plate. Motion in the other two directions did not differ significantly between locked and non-locked models.


Locked symphyseal plating systems can provide better stability than non-locked systems for anterior–posterior shear translation. More stability could potentially reduce the risk of failure of the plate or screws.


Symphyseal plating Locked plating Pelvis Biomechanics 



Funding and materials for the study were provided by DePuy Synthes.

Compliance with ethical requirements

Conflict of interest

Gregory Vrabec received a research grant and materials from DePuy Synthes to conduct the study. Ryan Godinsky, Loredana Guseila, Danielle Filipkowski, and John Elias declare no conflict of interest.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Orthopaedic SurgeryCleveland Clinic Akron GeneralAkronUSA
  2. 2.Department of ResearchCleveland Clinic Akron GeneralAkronUSA

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