title: Why does minimally invasive coracoclavicular ligament reconstruction using a flip button repair technique fail? An analysis of risk factors and complications.
abstract: OBJECTIVE
  Aim of the present study was to evaluate the risk factors for the failure of coracoclavicular ligament reconstruction using a flip button repair technique and to analyse complications related to this procedure.
  
  
  METHODS
  Seventy-one patients (3 female, 68 male) underwent surgical treatment using a flip button repair technique for an acute acromioclavicular joint dislocation. The following factors and its impact on clinical and radiographic outcome were assessed: age at trauma, interval between trauma and surgery, degree of displacement (according to Rockwood's classification), coracoid button position, button migration and post-operative appearance of ossifications.
  
  
  RESULTS
  Sixty-three patients were available for follow-up. The overall Constant score was 95.2 points (range 61-100 points) compared to 97 points (range 73-100 points) for the contralateral side (p = 0.05). Nine patients (14.3 %) needed surgical revision. Inappropriate positioning of the coracoid bone tunnel with subsequent button dislocation was the most frequently observed mode of failure (6 cases, 9.5 %). Button migration into the clavicle was associated with loss of reduction (p = 0.02). The patient's age at the time of trauma had a significant impact on the clinical outcome, whereas younger patients achieved better results (p = 0.02). The interval between trauma and surgery did not significantly affect the outcome (n.s.).
  
  
  CONCLUSIONS
  Good to excellent clinical results can be achieved with the presented surgical technique. The age of the patient at trauma had a significant influence on the functional outcome. Furthermore, placement of the coracoid button centrally under the coracoid base is crucial to prevent failure.
  
  
  METHODS
  IV.
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany. benedikt.schliemann@gmail.com.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Schliemann
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany.
authors.forename: Steffen B
authors.initials: SB
authors.lastname: Roßlenbroich
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany.
authors.forename: Kristian N
authors.initials: KN
authors.lastname: Schneider
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Theisen
authors.affiliation: Department of Orthopaedics and Trauma Surgery, Martin-Luther Hospital, Caspar-Theyß-Straße 27-31, 14193, Berlin, Germany.
authors.forename: Wolf
authors.initials: W
authors.lastname: Petersen
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Raschke
authors.affiliation: Department of Trauma, Hand and Reconstructive Surgery, University Hospital Münster, Waldeyerstraße 1, 48149, Münster, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Weimann
mesh_terms: D000173:Acromioclavicular Joint / Q000293:injuries* / Q000601:surgery; D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery*; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures / Q000379:methods*; D011183:Postoperative Complications; D019651:Plastic Surgery Procedures / Q000379:methods*; D012307:Risk Factors; D012783:Shoulder Dislocation / Q000601:surgery; D013997:Time Factors; D055815:Young Adult