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. Hypothesis: 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. Study Design: 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