title: Reliability of the classification and treatment of dislocations of the acromioclavicular joint.
abstract: BACKGROUND
  We evaluated interobserver and intraobserver reliability of the classification and treatment of acromioclavicular (AC) joint dislocations and assessed the impact of adding 3-dimensional computed tomography (3D CT) on the reliability of classification and treatment choice.
  
  
  METHODS
  Ten surgeons independently reviewed plain radiographs and 3D CT in 28 cases with AC joint dislocation. Images from each case were randomly presented to the observers, with plain radiographs alone being presented first, followed by plain radiographs plus 3D CT 2 weeks later. Four weeks later, they repeated the same survey to evaluate intraobserver reliability. Reliability was assessed on the basis of Fleiss κ values.
  
  
  RESULTS
  On the basis of plain radiographs alone, interobserver and intraobserver reliability of the Rockwood classification were fair (κ = .214) and moderate (κ = .474), respectively. Interobserver and intraobserver reliability of treatment were both fair (κ = .213 and .399, respectively). On the basis of a combination of plain radiographs and 3D CT, interobserver and intraobserver reliability of the Rockwood classification were slight (κ = .177) and moderate (κ = .565), respectively. Interobserver and intraobserver reliability of treatment were fair (κ = .253) and moderate (κ = .554), respectively. There were no significant differences in reliability between the two groups in terms of any κ values.
  
  
  CONCLUSIONS
  This study suggests an overall lack of reliability of the Rockwood classification of AC joint dislocations and of decisions regarding their treatment. There is especially poor agreement between experienced shoulder surgeons. The addition of 3D CT did not improve reliability of classification and treatment of AC joint dislocations.
authors.affiliation: Pain Research Center, Department of Orthopedic Surgery, Dongsan Medical Center, School of Medicine, Keimyung University, Daegu, South Korea. Electronic address: oscho5362@dsmc.or.kr.
authors.forename: Chul-Hyun
authors.initials: CH
authors.lastname: Cho
authors.affiliation: Department of Pathology, School of Medicine, Keimyung University, Daegu, South Korea.
authors.forename: Ilseon
authors.initials: I
authors.lastname: Hwang
authors.affiliation: Department of Orthopedic Surgery, Yeungnam University Hospital, Daegu, South Korea.
authors.forename: Jae-Sung
authors.initials: JS
authors.lastname: Seo
authors.affiliation: Department of Orthopedic Surgery, Daegu Catholic University Medical Center, Daegu, South Korea.
authors.forename: Chang-Hyuk
authors.initials: CH
authors.lastname: Choi
authors.affiliation: Department of Orthopedic Surgery, Ulsan University Hospital, Ulsan, South Korea.
authors.forename: Sang-Hun
authors.initials: SH
authors.lastname: Ko
authors.affiliation: Department of Orthopedic Surgery, Gyeongsang National University Hospital, Jinju, South Korea.
authors.forename: Hyung Bin
authors.initials: HB
authors.lastname: Park
authors.affiliation: Department of Orthopedic Surgery, Gumi CHA Hospital, CHA University, Gumi, South Korea.
authors.forename: Jinmyoung
authors.initials: J
authors.lastname: Dan
mesh_terms: D000173:Acromioclavicular Joint / Q000293:injuries*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002983:Clinical Competence; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D004204:Joint Dislocations / Q000145:classification* / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D011446:Prospective Studies; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Acromioclavicular joint; Rockwood classification; dislocation; interobserver; intraobserver; reliability; treatment