title: Biomechanical evaluation of a coracoclavicular and acromioclacicular ligament reconstruction technique utilizing a single continuous intramedullary free tendon graft.
abstract: BACKGROUND
  Reconstruction of only the coracoclavicular (CC) ligaments may restore superior-inferior (S-I) but not anterior-posterior (A-P) stability of the acromioclavicular (AC) joint. Concomitant reconstruction of both the AC and CC ligaments may more reliably restore intact biomechanical characteristics of the AC joint.
  
  
  METHODS
  Ten matched pairs of shoulders were utilized. Five specimens underwent CC ligament reconstruction while an equal number underwent combined AC and CC ligament reconstruction utilizing an intramedullary tendon graft. Each of the reconstructions was compared with the intact contralateral control. Translational and load to failure characteristics were compared between groups.
  
  
  RESULTS
  No difference was found in S-I translation between intact specimens and CC-only reconstructions (P = .20) nor between intact specimens and AC/CC reconstructions (P = .33) at 10 Newton (N) loads. Significant differences were noted in A-P translation between intact specimens and CC-only reconstructions (P < .001) but no difference in A-P translation between intact specimens and AC/CC reconstructions (P = .34).
  
  
  CONCLUSIONS
  The A-P and S-I translational biomechanical characteristics of the AC joint were restored using the new technique described. Reconstruction of the CC ligaments only (versus AC/CC combined) led to significantly increased translational motion in the A-P plane as compared to intact control specimens.
authors: Department of Orthopedic Surgery, Stanford University, Stanford, CA, USA. geoffa7@yahoo.com
authors: Geoffrey D
authors: GD
authors: Abrams
authors: Michelle H
authors: MH
authors: McGarry
authors: Nickul S
authors: NS
authors: Jain
authors: Michael T
authors: MT
authors: Freehill
authors: Sang-Jin
authors: SJ
authors: Shin
authors: Emilie V
authors: EV
authors: Cheung
authors: Thay Q
authors: TQ
authors: Lee
authors: Marc R
authors: MR
authors: Safran
mesh_terms: D000173:Acromioclavicular Joint / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D005260:Female; D006085:Graft Survival; D006801:Humans; D007593:Joint Instability / Q000517:prevention & control; D008023:Ligaments, Articular / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019651:Plastic Surgery Procedures / Q000379:methods*; D012016:Reference Values; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D013709:Tendon Transfer / Q000379:methods*; D013710:Tendons / Q000637:transplantation; D013718:Tensile Strength