title: Arthroscopically guided navigation for repair of acromioclavicular joint dislocations: a safe technique with reduced intraoperative radiation exposure.
abstract: BACKGROUND
  Accuracy evaluation of navigated image free placement of double cortical fixation buttons for coracoclavicular tunnel position in comparison to conventional drill guide based placement.
  
  
  METHODS
  Twenty-six patients with acute acromioclavicular joint instability were included in this non-randomized cohort study. All patients were treated with a Double- TightRope technique. In 13 cases the conventional drill guide based placement was used (group 1). In 13 patients surgery was performed as a navigated procedure with a fluoro-free optoelectronic system (group 2). The number of coracoclavicular drillings per patient (First pass accuracy; FPA (%)) was documented, the subcoracoidal position of the fixation buttons has been evaluated and graded as "intended position achieved (IPA)" or "intended position not achieved (IPnA)".
  
  
  RESULTS
  In group 1 drilling had to be repeated in four patients (30.8 %) to achieve proper placement of the subcoracoidal fixation buttons. 100 % first pass accuracy was observed in group 2 (p = 0.03). In group 1, the intended position of the subcoracoid buttons was not achieved (IPnA) in six patients (46.2 %). In group 2 all intended positions were achieved (p = 0.005).
  
  
  CONCLUSIONS
  Arthroscopic controlled fluoro-free navigated coracoclavicular drilling for the repair of acromioclavicular joint dislocation has higher first pass accuracy in comparison to conventional drill guide based placement. Therefore the navigation enables a precise position of the drill holes, may reduce the risk of an iatrogenic coracoid fracture and migration of fixation devices.
  
  
  BACKGROUND
  Local institutional review board No. 061-14-10032014.
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Theopold
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Marquass
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: von Dercks
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Mütze
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Ralf
authors.initials: R
authors.lastname: Henkelmann
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Josten
authors.affiliation: Department of Orthopaedics, Trauma and Plastic Surgery, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany ; Devision of Arthroscopy, Joint Surgery and Sport Injuries, University of Leipzig, Liebigstr. 20, 04103 Leipzig, Germany.
authors.forename: Pierre
authors.initials: P
authors.lastname: Hepp
keywords: AC joint dislocation; AC joint injuries; AC joint reconstruction; Coracoclavicular; Navigation; Shoulder