title: Biomechanical evaluation of minimally invasive repairs for complete acromioclavicular joint dislocation.
abstract: BACKGROUND
  The conventional coracoclavicular ligament augmentation with a single polydioxanone loop has been shown to have some pivotal disadvantages.
  
  
  OBJECTIVE
  A minimally invasive flip button/polydioxanone repair provides similar biomechanical properties to the conventional polydioxanone cerclage around the coracoid. However, the authors expected a difference in linear stiffness, ultimate load, and permanent elongation between suture anchor repairs and polydioxanone repairs.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  The tensile fixation strength of 4 different minimally invasive repairs was tested in a porcine metatarsal model: (1) 1.3-mm single polydioxanone cerclage with a subcoracoidal flip button fixation, (2) 1.3-mm single polydioxanone cerclage, (3) Twinfix Ti 3.5-mm/Ultrabraid 2-suture anchor, and (4) Twinfix Ti 5.0-mm/Ultrabraid 2-suture anchor. The testing protocol included cyclic superoinferior loading and a subsequent load to failure trial.
  
  
  RESULTS
  The flip button repair (646 N) and the conventional polydioxanone banding (663 N) revealed significant higher ultimate loads than did the suture anchor repairs (295 and 331 N, respectively; P < .001), whereas no significant differences were found for the elongation behavior under cyclic loading.
  
  
  CONCLUSIONS
  There was no significant difference between the 2 polydioxanone repairs. The ultimate load of the flip button procedure reaches the level of the native coracoclavicular ligament complex as it has been quantified in the literature.
  
  
  CONCLUSIONS
  Although the biomechanical results comparing a minimally invasive flip button procedure versus a conventional polydioxanone cerclage are similar, the authors recommend the flip button procedure because of its minimally invasive approach and the secure subcoracoidal fixation technique with a minimized risk of anterior loop dislocation and neurovascular damage.
authors.affiliation: Department of Traumatology, Hand, and Reconstructive Surgery, University Hospital Muenster, Waldeyerstr. 1, 48149 Muenster, Germany. Mathias.Wellmann@ukmuenster.de
authors.forename: Mathias
authors.initials: M
authors.lastname: Wellmann
authors.forename: Thore
authors.initials: T
authors.lastname: Zantop
authors.forename: Andre
authors.initials: A
authors.lastname: Weimann
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Raschke
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
mesh_terms: D000173:Acromioclavicular Joint / Q000601:surgery*; D000818:Animals; D001696:Biomechanical Phenomena; D005858:Germany; D019060:Minimally Invasive Surgical Procedures; D017063:Outcome Assessment, Health Care; D012783:Shoulder Dislocation / Q000601:surgery*; D053831:Surgical Fixation Devices; D013552:Swine