title: Incidence of and risk factors for traumatic anterior shoulder dislocation: an epidemiologic study in high-school rugby players.
abstract: BACKGROUND
  The incidence of reinjuries due to glenohumeral instability and the major risk factors for primary anterior shoulder dislocation in youth rugby players have been unclear.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the incidence, mechanisms, and intrinsic risk factors of shoulder dislocation in elite high-school rugby union teams during the 2012 season.
  
  
  METHODS
  A total of 378 male rugby players from 7 high-school teams were investigated by use of self-administered preseason and postseason questionnaires.
  
  
  RESULTS
  The prevalence of a history of shoulder dislocation was 14.8%, and there were 21 events of primary shoulder dislocation of the 74 overall shoulder injuries that were sustained during the season (3.2 events per 1000 player-hours of match exposure). During the season, 54.3% of the shoulders with at least one episode of shoulder dislocation had reinjury. This study also indicated that the persistence of glenohumeral instability might affect the player's self-assessed condition, regardless of the incidence during the current season. By a multivariate logistic regression method, a history of shoulder dislocation on the opposite side before the season was found to be a risk factor for contralateral primary shoulder dislocation (odds ratio, 3.56; 95% confidence interval, 1.27-9.97; P = .02).
  
  
  CONCLUSIONS
  High-school rugby players with a history of shoulder dislocation are not playing at full capacity and also have a significant rate of reinjury as well as a high risk of dislocating the other shoulder. These findings may be helpful in deciding on the proper treatment of primary anterior shoulder dislocation in young rugby players.
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan. Electronic address: k-saki@luck.ocn.ne.jp.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Keio University Rugby Football Club, Yokohama, Kanagawa, Japan.
authors.forename: Chihiro
authors.initials: C
authors.lastname: Ota
authors.affiliation: Department of Sports Medicine, International Budo University, Katsuura, Chiba, Japan.
authors.forename: Shingo
authors.initials: S
authors.lastname: Urayama
authors.affiliation: Mejiro Orthopaedic and Internal Medicine Clinic, Toshima, Tokyo, Japan.
authors.forename: Nobukazu
authors.initials: N
authors.lastname: Maki
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan.
authors.forename: Masataka
authors.initials: M
authors.lastname: Nagayama
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan.
authors.forename: Takefumi
authors.initials: T
authors.lastname: Kaketa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takazawa
authors.affiliation: Department of Orthopaedic Surgery, Juntendo University Faculty of Medicine, Bunkyo, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000293:Adolescent; D001265:Athletic Injuries / Q000453:epidemiology* / Q000601:surgery; D005538:Football / Q000293:injuries*; D006801:Humans; D015994:Incidence; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012574:Schools / Q000706:statistics & numerical data; D012783:Shoulder Dislocation / Q000453:epidemiology* / Q000209:etiology; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000601:surgery
keywords: Rugby; dislocation; epidemiology; glenohumeral instability; high school; shoulder injury