title: Measure of horizontal and vertical displacement of the acromioclavicular joint after cutting ligament using X-ray and opto-electronic system.
abstract: BACKGROUND
  Surgical versus orthopedic treatments of acromioclavicular disjunction are still debated. The aim of this study was to measure horizontal and vertical acromion's displacement after cutting the ligament using standard X-ray and an opto-electronic system on cadaver.
  
  
  METHODS
  Ten cadaveric shoulders were studied. A sequential ligament's section was operated by arthroscopy. The sequence of cutting was chosen to fit with Rockwood's grade. The displacement of the acromion was measured on standard X-ray and with an opto-electronic system allowing measuring of the horizontal displacement. Statistical comparisons were performed using a paired Student's t test with significance set at p < 0.05.
  
  
  RESULTS
  Cutting the coracoclavicular ligament and delto-trapezius muscles cause a statistical downer displacement of the acromion, but not after sectioning the acromioclavicular ligament. The contact surface between the acromion and the clavicle decreases statistically after sectioning the acromioclavicular ligament and the coracoclavicular ligament with no effect of sectioning the delto-trapezius muscles. Those results are superposing with those dealing with the anterior translation.
  
  
  CONCLUSIONS
  The measure concerning the acromioclavicular distance and the coracoclavicular distance are superposing with those of Rockwood. However, there is a significant horizontal translation after cutting the acromioclavicular ligament. Taking into account this displacement, it may be interesting to choose either surgical or orthopedic treatment.
  
  
  CONCLUSIONS
  There is a correlation between anatomical damage and importance of instability. Horizontal instability is misevaluated in clinical practice.
authors.affiliation: Department of Trauma and Orthopaedic Surgery, Université de Caen, Caen, France. grochcongar@gmail.com
authors.forename: Goulven
authors.initials: G
authors.lastname: Rochcongar
authors.forename: Sébastien
authors.initials: S
authors.lastname: Emily
authors.forename: Benoit
authors.initials: B
authors.lastname: Lebel
authors.forename: Vincent
authors.initials: V
authors.lastname: Pineau
authors.forename: Gilles
authors.initials: G
authors.lastname: Burdin
authors.forename: Christophe
authors.initials: C
authors.lastname: Hulet
mesh_terms: D000173:Acromioclavicular Joint / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D000368:Aged; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D008023:Ligaments, Articular / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery; D019637:Orthopedic Procedures