title: The biomechanical stability of distal clavicle excision versus symmetric acromioclavicular joint resection.
abstract: BACKGROUND
  Treatment for acromioclavicular (AC) joint pain may include distal clavicle excision (DCE). It is possible that DCE can disrupt the surrounding ligaments, leading to increased AC joint laxity.
  
  
  OBJECTIVE
  To determine the load to failure and stiffness of the AC joint after DCE and symmetric acromioclavicular joint resection (ACJR).
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Specimens were randomly assigned to 1 of 2 groups: 1-cm DCE (n = 10) or symmetric (5-mm excision of acromion and distal clavicle) ACJR (n = 10). The specimens were loaded intact in the anterior-posterior plane to determine anteroposterior translation. This was repeated after surgery and compared. The specimens were loaded at 2 mm/s until clinical failure. Force and displacement were recorded, and stiffness was calculated.
  
  
  RESULTS
  The peak load to failure for the DCE group was 387.8 N (standard error of the mean [SEM], 31.4 N) and for the ACJR group was 468.5 N (SEM, 30.9 N) (P = .035). The average stiffness for the DCE group was 35.2 N/mm (SEM, 2.5 N/mm) and for the ACJR group was 37.4 N/mm (SEM, 2.3 N/mm) (P = .11). There was no significant difference in the anteroposterior translation before and after resection for either group (P > .05).
  
  
  CONCLUSIONS
  This cadaveric study demonstrates that the anterior-posterior load to clinical failure of the AC joint after 5 mm of resection from the distal clavicle and medial acromion is significantly greater than 1 cm of the resected distal clavicle alone.
  
  
  CONCLUSIONS
  Performing ACJR may improve joint stability, leading to fewer complications when compared with DCE.
authors.affiliation: Detroit Medical Center Sports Medicine, 28800 Ryan Road, Suite 220, Warren, MI 48092, USA.
authors.forename: Nikhil G
authors.initials: NG
authors.lastname: Pandhi
authors.forename: Amanda O
authors.initials: AO
authors.lastname: Esquivel
authors.forename: Jason D
authors.initials: JD
authors.lastname: Hanna
authors.forename: David W
authors.initials: DW
authors.lastname: Lemos
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Staron
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lemos
mesh_terms: D000173:Acromioclavicular Joint / Q000503:physiopathology / Q000601:surgery*; D000368:Aged; D018771:Arthralgia / Q000601:surgery*; D001696:Biomechanical Phenomena; D002102:Cadaver; D002968:Clavicle / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012785:Shoulder Joint / Q000503:physiopathology / Q000601:surgery*