title: Mechanisms for noncontact anterior cruciate ligament injuries: knee joint kinematics in 10 injury situations from female team handball and basketball.
abstract: BACKGROUND
  The mechanism for noncontact anterior cruciate ligament injury is still a matter of controversy. Video analysis of injury tapes is the only method available to extract biomechanical information from actual anterior cruciate ligament injury cases.
  
  
  OBJECTIVE
  This article describes 3-dimensional knee joint kinematics in anterior cruciate ligament injury situations using a model-based image-matching technique.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  Ten anterior cruciate ligament injury video sequences from women's handball and basketball were analyzed using the model-based image-matching method.
  
  
  RESULTS
  The mean knee flexion angle among the 10 cases was 23° (range, 11°-30°) at initial contact (IC) and had increased by 24° (95% confidence interval [CI], 19°-29°) within the following 40 milliseconds. The mean valgus angle was neutral (range, -2° to 3°) at IC, but had increased by 12° (95% CI, 10°-13°) 40 milliseconds later. The knee was externally rotated 5° (range, -5° to 12°) at IC, but rotated internally by 8° (95% CI, 2°-14°) during the first 40 milliseconds, followed by external rotation of 17° (95% CI, 13°-22°). The mean peak vertical ground-reaction force was 3.2 times body weight (95% CI, 2.7-3.7), and occurred at 40 milliseconds after IC (range, 0-83).
  
  
  CONCLUSIONS
  Based on when the sudden changes in joint angular motion and the peak vertical ground-reaction force occurred, it is likely that the anterior cruciate ligament injury occurred approximately 40 milliseconds after IC. The kinematic patterns were surprisingly consistent among the 10 cases. All players had immediate valgus motion within 40 milliseconds after IC. Moreover, the tibia rotated internally during the first 40 milliseconds and then external rotation was observed, possibly after the anterior cruciate ligament had torn. These results suggest that valgus loading is a contributing factor in the anterior cruciate ligament injury mechanism and that internal tibial rotation is coupled with valgus motion. Prevention programs should focus on acquiring a good cutting and landing technique with knee flexion and without valgus loading of the knee.
authors.affiliation: Hideyuki Koga, Oslo Sports Trauma Research Center, Norwegian School of Sport Sciences, PO Box 4014 Ullevaal Stadion, 0806 Oslo, Norway. koga-z@rg7.so-net.ne.jp
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Koga
authors.forename: Atsuo
authors.initials: A
authors.lastname: Nakamae
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Shima
authors.forename: Junji
authors.initials: J
authors.lastname: Iwasa
authors.forename: Grethe
authors.initials: G
authors.lastname: Myklebust
authors.forename: Lars
authors.initials: L
authors.lastname: Engebretsen
authors.forename: Roald
authors.initials: R
authors.lastname: Bahr
authors.forename: Tron
authors.initials: T
authors.lastname: Krosshaug
mesh_terms: D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000453:epidemiology / Q000209:etiology*; D001490:Basketball / Q000293:injuries*; D001696:Biomechanical Phenomena; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D007718:Knee Injuries / Q000453:epidemiology / Q000209:etiology*; D015999:Multivariate Analysis; D009664:Norway / Q000453:epidemiology; D011187:Posture; D016059:Range of Motion, Articular; D012307:Risk Factors; D013977:Tibia; D014743:Videotape Recording