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, John Joseph Elias

Research output: Contribution to journalArticlepeer-review


Purpose: 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. Methods: 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). Results: 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. Conclusions: 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.

Original languageEnglish (US)
Pages (from-to)1-6
Number of pages6
JournalEuropean Journal of Trauma and Emergency Surgery
StateAccepted/In press - Mar 17 2016
Externally publishedYes


  • Biomechanics
  • Locked plating
  • Pelvis
  • Symphyseal plating

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine
  • Critical Care and Intensive Care Medicine
  • Emergency Medicine


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