title: A comparison of conventional versus locking plates in intraarticular calcaneus fractures: a biomechanical study in human cadavers.
abstract: BACKGROUND
  Internal fixation of displaced intraarticular calcaneal fractures in patients older than 50 years remains controversial. This is, in many cases, due to fear of loss of fixation and the risk of implant failure in osteoporotic bone. It is the objective of this study to compare the fixation strength obtained using calcaneal plates with and without locking screws, in the fixation of osteoporotic cadaveric intraarticular calcaneal fractures.
  
  
  METHODS
  In seven pairs of fresh frozen lower limbs cadavers, intraarticular calcaneal fractures were created with a dynamic single impact loading device and stabilized using either the low profile locking plate, or the conventional calcaneus plate. Radiographs were obtained to assess reduction. The specimens were then subjected to cyclic loading followed by loading to failure, using matched pairs of cadaveric lower limbs. The Wilcoxon signed rank test was used to test for differences in the results.
  
  
  RESULTS
  The locking plate showed a significant lower irreversible deformation during cyclic loading and a significant higher load to failure. The difference between the ultimate displacement, and work to failure was not significant. A low bone mineral content in the area of the posterior facet correlated only in the conventional plate group with increased irreversible deformation.
  
  
  CONCLUSIONS
  This study supports the mechanical viability of using locking calcaneal plates for the fixation of intraarticular calcaneal fractures in elderly patients.
authors.affiliation: Fremantle Orthopaedic Unit, University of Western Australia, Alma Street, B. Block, Level 6, Fremantle, Western Australia 6160, Australia. nkstoffel@hotmail.com
authors.forename: Karl
authors.initials: K
authors.lastname: Stoffel
authors.forename: Grant
authors.initials: G
authors.lastname: Booth
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Rohrl
authors.forename: Markus
authors.initials: M
authors.lastname: Kuster
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena / Q000379:methods*; D015519:Bone Density; D001842:Bone and Bones / Q000033:anatomy & histology* / Q000473:pathology*; D002102:Cadaver; D005260:Female; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000175:diagnosis* / Q000473:pathology*; D006801:Humans; D016268:Internal Fixators; D035002:Lower Extremity / Q000473:pathology; D008297:Male; D008422:Materials Testing; D010024:Osteoporosis / Q000473:pathology*; D013314:Stress, Mechanical; D013718:Tensile Strength