title: A biomechanical study on proximal plate fixation techniques in periprosthetic femur fractures.
abstract: BACKGROUND
  Proximal plate fixation is a crucial factor in osteosynthesis of periprosthetic femur fractures. Stability and strength of different fixation concepts for proximal plate fixation were compared.
  
  
  METHODS
  Twelve fresh frozen, bone mineral density matched human femora, instrumented with cemented hip endoprosthesis were osteotomized simulating a Vancouver B1 fracture. Specimens were instrumented with locking compression plates, fixed proximally with either locking attachment plate (LAP), monocortical screws, cerclage plus monocortical screws (1cerclage) or cerclages only (4cerclages). Cyclic testing was performed with monotonically increasing load until failure. Relative movements at the proximal plate-femur interface were registered by motion tracking.
  
  
  RESULTS
  The LAP construct exhibited a significantly longer cumulative survival (failure criterion 1mm separation at the proximal plate fixation) compared to the monocortical (p=0.048) and 4cerclages constructs (p=0.012) but not to 1cerclage constructs.
  
  
  CONCLUSIONS
  Bicortical screw anchorage improves proximal plate fixation in periprosthetic fractures. The cerclage-screw combination is a valuable alternative especially in osteoporotic bone.
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, CH-7270 Davos-Platz, Switzerland; Department of Trauma, Hand and Reconstructive Surgery, Friedrich-Schiller-University Jena, Erlanger Allee 101, D-07747 Jena, Germany. Electronic address: mark.lenz@med.uni-jena.de.
authors.forename: Mark
authors.initials: M
authors.lastname: Lenz
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, CH-7270 Davos-Platz, Switzerland. Electronic address: stephan.perren@aofoundation.org.
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Perren
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, CH-7270 Davos-Platz, Switzerland. Electronic address: boyko.gueorguiev@aofoundation.org.
authors.forename: Boyko
authors.initials: B
authors.lastname: Gueorguiev
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, CH-7270 Davos-Platz, Switzerland. Electronic address: geoff.richards@aofoundation.org.
authors.forename: Robert G
authors.initials: RG
authors.lastname: Richards
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, Friedrich-Schiller-University Jena, Erlanger Allee 101, D-07747 Jena, Germany. Electronic address: gunther.hofmann@med.uni-jena.de.
authors.forename: Gunther O
authors.initials: GO
authors.lastname: Hofmann
authors.affiliation: Department of Traumatology, British Hospital, Av. Italia 2420, Montevideo, Uruguay. Electronic address: AaFernan@netgate.com.uy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Fernandez dell'Oca
authors.affiliation: Department of Medical Technology Development, BG Trauma Hospital Tübingen, Schnarrenbergstrasse 95, D-72076 Tübingen, Germany. Electronic address: DHoentzsch@bgu-tuebingen.de.
authors.forename: Dankward
authors.initials: D
authors.lastname: Höntzsch
authors.affiliation: AO Research Institute Davos, Clavadelerstrasse 8, CH-7270 Davos-Platz, Switzerland. Electronic address: markus.windolf@aofoundation.org.
authors.forename: Markus
authors.initials: M
authors.lastname: Windolf
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D005264:Femoral Fractures / Q000601:surgery*; D005593:Fracture Fixation, Internal; D006801:Humans; D008297:Male; D008422:Materials Testing; D010027:Osteotomy; D057068:Periprosthetic Fractures / Q000601:surgery*; D016474:Weight-Bearing
keywords: Cerclage; Hip arthroplasty; Locking attachment plate; Periprosthetic fracture