title: Higher stability with locking plates in hand surgery? Biomechanical investigation of the TriLock system in a fracture model.
abstract: OBJECTIVE
  The aim of this study was to determine the biomechanical characteristics of locking plates with the TriLock system with different design and screw settings compared to a non-locking plate in a diaphyseal metacarpal fracture.
  
  
  METHODS
  Oblique diaphyseal shaft fractures in porcine metacarpal bones were created in a biomechanical fracture model. After reduction they were fixed with three different locking plates with the TriLock interlocking mechanism or a non-locking linear plate in mono- or bicortical screw fixations. In load to failure tests the maximum load and stiffness were measured.
  
  
  RESULTS
  For linear plates, the maximum load was higher for the non-locking plate compared with the locking plate. The maximum load could be increased for the locking plates using a double-row design and a higher screw number. No differences were found for the stiffness between all groups. In contrast to the non-locking plate, the mode of failure of the locking plates in many cases (86 %) was a loss of the interlocking mechanism.
  
  
  CONCLUSIONS
  The results suggest that the locking plates with the TriLock system achieve no higher stability compared to a non-locking plate in load to failure tests. Adaptions to increase the stability of the interlocking mechanism are desirable.
authors.affiliation: Department of Trauma, Hand, Plastic and Reconstructive Surgery, University Clinics of Würzburg, Oberduerrbacher Strasse 6, 97080, Würzburg, Germany. doht_s@klinik.uni-wuerzburg.de
authors.forename: Stefanie
authors.initials: S
authors.lastname: Doht
authors.forename: Hendrik
authors.initials: H
authors.lastname: Jansen
authors.forename: Rainer
authors.initials: R
authors.lastname: Meffert
authors.forename: Sönke
authors.initials: S
authors.lastname: Frey
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D050823:Hand Joints / Q000293:injuries* / Q000601:surgery; D007593:Joint Instability / Q000601:surgery*; D008422:Materials Testing; D050279:Metacarpal Bones / Q000293:injuries* / Q000601:surgery; D023421:Models, Animal; D013314:Stress, Mechanical; D013552:Swine