title: Anatomic considerations of transclavicular-transcoracoid drilling for coracoclavicular ligament reconstruction.
abstract: OBJECTIVE
  Acromioclavicular (AC) joint injuries vary in severity and damage to the AC and coracoclavicular (CC) ligaments. We hypothesized that transclavicular-transcoracoid drilling techniques, which allow for arthroscopic passage and fixation of tendon grafts in bone sockets to replace the insufficient conoid and trapezoid ligaments, cannot restore the footprints of the conoid and trapezoid ligaments without significant risk of cortical breach and coracoid fracture.
  
  
  METHODS
  Data from a prospective computed tomography shoulder registry were used to create 23 distinct shoulders. Three-dimensional models were constructed the shoulders in which virtual CC ligament reconstruction tunnels were superimposed using previously described anatomic distances and landmarks.
  
  
  RESULTS
  Transclavicular-transcoracoid techniques resulted in mean remaining medial and lateral wall thicknesses before cortical breach of 7.3 ± 1.7 and 7.0 ± 1.6 mm, respectively. The distance from the entry point of this tunnel from the anatomic midpoint of the CC ligaments was 9.9 ± 2.2 mm. Attempts to recapitulate the CC ligament anatomy by using anatomic distances and landmarks with transcoracoid, transclavicular techniques resulted in medial cortical breach of the coracoid in 91.3% of the shoulders.
  
  
  CONCLUSIONS
  Transclavicular-transcoracoid reconstructive techniques cannot restore the footprints of the conoid and trapezoid ligaments without significant risk of cortical breach and fracture. Attempts to correct this nonanatomic configuration by creating a tunnel based on the anatomic footprints results in a nearly universal medial cortical breach of the coracoid process.
authors.affiliation: MedSport, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI 48106, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Coale
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Hollister
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Dines
authors.forename: Answorth A
authors.initials: AA
authors.lastname: Allen
authors.forename: Asheesh
authors.initials: A
authors.lastname: Bedi
mesh_terms: D000173:Acromioclavicular Joint / Q000033:anatomy & histology*; D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D019637:Orthopedic Procedures / Q000379:methods*; D055815:Young Adult