title: Acromioclavicular joint injuries in National Collegiate Athletic Association football: data from the 2004-2005 through 2008-2009 National Collegiate Athletic Association Injury Surveillance System.
abstract: BACKGROUND
  Injuries to the shoulder are common in collegiate football, and injuries to the acromioclavicular (AC) joint have previously accounted for up to 41% of all shoulder injuries.
  
  
  OBJECTIVE
  To determine the incidence and epidemiology of injury to the AC joint in National Collegiate Athletic Association (NCAA) football athletes.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  The NCAA Injury Surveillance System (ISS) men's football database was reviewed from the 2004-2009 playing seasons. The exposure data set from the same years was reviewed for the purposes of computing rates of injury per athlete exposure (AE). The injury rate (number of injuries divided by number of AEs) was computed per 10,000 AEs for competition and practice exposures. Ninety-five percent confidence intervals (95% CIs) for the incidence rates were calculated using assumptions of a Poisson distribution.
  
  
  RESULTS
  According to the estimates made by the NCAA ISS, a total of 748 injuries to the AC joint occurred in NCAA football players during 2,222,155 AEs, accounting for 4.49% of all injuries sustained during this 5-year surveillance period. The overall rate of injury was 3.34 per 10,000 AEs (95% CI, 3.10-3.59). Players were 11.68 (95% CI, 10.11-13.49) times more likely to sustain an injury in games than practices. Partial sprains (types I or II) accounted for 96.4% of injuries, while complete sprains (≥type III) accounted for the remaining 3.6%. The average amount of time lost per injury was 11.61 days. Complete sprains resulted in a mean time loss of 31.9 days (95% CI, 24.4-39.6) while partial injuries resulted in 11.0 days lost (95% CI, 9.6-12.3). Overall, 2.41% of injuries underwent surgical intervention, with 22.2% of complete sprains and 1.7% of partial injuries resulting in surgery. Complete sprains of the AC joint were 13.5 (95% CI, 4.63-35.26) times more likely to result in surgical intervention than partial sprains. The majority of injuries (71.93%) resulted from contact with another player and 47.09% occurred while tackling or being tackled. Of all injuries, 47.63% occurred during offensive plays, while defense accounted for 20.77%.
  
  
  CONCLUSIONS
  AC joint injuries in NCAA football players are predominantly low-grade sprains, leading to approximately 12 days of lost competition. The few severe sprains that occurred often resulted in surgery or required approximately 5 weeks of rehabilitation.
authors.affiliation: Department of Orthopaedic Surgery, Stanford University, 450 Broadway Street, Pavilion C, 4th floor, Redwood City, CA 94063-6342, USA. jdragoo@stanford.edu
authors.forename: Jason L
authors.initials: JL
authors.lastname: Dragoo
authors.forename: Hillary J
authors.initials: HJ
authors.lastname: Braun
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Bartlinski
authors.forename: Alex H S
authors.initials: AH
authors.lastname: Harris
mesh_terms: D000173:Acromioclavicular Joint / Q000293:injuries*; D000328:Adult; D001265:Athletic Injuries / Q000453:epidemiology*; D005538:Football / Q000293:injuries* / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male