Biomechanical evaluation of periprosthetic refractures following distal femur locking plate fixation

Jamie Alexander, Randal P. Morris, David Kaimrajh, Edward Milne, Loren Latta, Adam Flink, Ronald Lindsey

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Introduction Distal femur fractures proximal to total knee femoral component constitutes the most prevalent type of periprosthetic fracture, and plate fixation treatment is associated with a 7.7% incidence of refracture proximal to the plate. The primary objective of this study was to compare proximal fixation techniques of a periprosthetic distal femur fracture plate in an osteoporotic bone model. The secondary objective was to determine the subsequent periprosthetic plate fracture pattern and/or complexity associated with each proximal plate fixation configuration. Materials and methods A segmental defect was created in 21 synthetic osteoporotic adult femurs 6 cm proximal to the distal femur and all specimens were stabilised with a 246 mm locking femur plate. Fixation in the most proximal hole was varied by use of either a cerclage cable, unicortical locking screw, or a bicortical locking screw. Specimens were tested to failure in simultaneous eccentric compression and torsion. Results Proximal cerclage fixation demonstrated higher mean maximum axial force at failure (4142.67 ± 178.71 N, p <0.001), stiffness (443.8 ± 61.64 N/mm), and maximum torque (20.9 ± 0.93 N m, p <0.001). Unicortical and bicortical screw refractures occurred at the screw, cerclage wire refractures occurred at the first proximal screw distal to the cerclage. Conclusions In periprosthetic distal femur fracture locking plate fixation, proximal hole stabilization with a cerclage wire tolerates significantly higher failure forces while distributing forces distal to the area within the plate fixation. Cerclage wiring may be an option in distal femur periprosthetic fractures to alleviate stress risers in vulnerable bone.

Original languageEnglish (US)
Pages (from-to)2368-2373
Number of pages6
JournalInjury
Volume46
Issue number12
DOIs
StatePublished - Dec 1 2015

Keywords

  • Biomechanics
  • Cerclage wiring
  • Locking plate fixation
  • Periprosthetic fixation
  • Refractures

ASJC Scopus subject areas

  • Emergency Medicine
  • Orthopedics and Sports Medicine

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