title: Mechanisms of anterior cruciate ligament injury in basketball: video analysis of 39 cases.
abstract: BACKGROUND
  The mechanisms of anterior cruciate ligament injury in basketball are not well defined.
  
  
  OBJECTIVE
  To describe the mechanisms of anterior cruciate ligament injury in basketball based on videos of injury situations.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Six international experts performed visual inspection analyses of 39 videos (17 male and 22 female players) of anterior cruciate ligament injury situations from high school, college, and professional basketball games. Two predefined time points were analyzed: initial ground contact and 50 milliseconds later. The analysts were asked to assess the playing situation, player behavior, and joint kinematics.
  
  
  RESULTS
  There was contact at the assumed time of injury in 11 of the 39 cases (5 male and 6 female players). Four of these cases were direct blows to the knee, all in men. Eleven of the 22 female cases were collisions, or the player was pushed by an opponent before the time of injury. The estimated time of injury, based on the group median, ranged from 17 to 50 milliseconds after initial ground contact. The mean knee flexion angle was higher in female than in male players, both at initial contact (15 degrees vs 9 degrees , P = .034) and at 50 milliseconds later (27 degrees vs 19 degrees , P = .042). Valgus knee collapse occurred more frequently in female players than in male players (relative risk, 5.3; P = .002).
  
  
  CONCLUSIONS
  Female players landed with significantly more knee and hip flexion and had a 5.3 times higher relative risk of sustaining a valgus collapse than did male players. Movement patterns were frequently perturbed by opponents.
  
  
  CONCLUSIONS
  Preventive programs to enhance knee control should focus on avoiding valgus motion and include distractions resembling those seen in match situations.
authors.affiliation: Oslo Sports Trauma Research Center, Department of Sports Medicine, Norwegian School of Sport Sciences, Oslo, Norway. tron.krosshaug@nih.no
authors.forename: Tron
authors.initials: T
authors.lastname: Krosshaug
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nakamae
authors.forename: Barry P
authors.initials: BP
authors.lastname: Boden
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: Gerald
authors.initials: G
authors.lastname: Smith
authors.forename: James R
authors.initials: JR
authors.lastname: Slauterbeck
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Hewett
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
mesh_terms: D000293:Adolescent; D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries; D001490:Basketball; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D014481:United States; D014741:Video Recording