title: Evaluation of a two dimensional analysis method as a screening and evaluation tool for anterior cruciate ligament injury.
abstract: BACKGROUND
  Increased knee valgus predicts the risk of anterior cruciate ligament (ACL) injury, particularly in women. Reducing injury rates thus relies on detecting and continually evaluating people with relatively large valgus motions.
  
  
  OBJECTIVE
  To examine the potential of a two dimensional (2D) video analysis method for screening for excessive valgus.
  
  
  METHODS
  Ten female and 10 male National Collegiate Athletic Association basketball players had three dimensional (3D) knee valgus and two dimensional (2D) frontal plane knee angle quantified during side step, side jump, and shuttle run tasks. 3D valgus was quantified from external marker coordinates using standard techniques, and 2D data were obtained from both the frontal plane projections of these coordinates (2D-Mot) and manual digitization of digital video footage (2D-Cam). A root mean square (RMS) error was calculated between 2D-Mot and 2D-Cam data to evaluate the reliability of the latter. Correlations between 2D-Cam and 3D data (intersubject and intrasubject) were also conducted, and regression slope and r2 values obtained.
  
  
  RESULTS
  2D-Cam and 2D-Mot data were consistent for side step (RMS = 1.7 degrees) and side jump (RMS = 1.5 degrees) movements. Between subjects, 2D-Cam and 3D data correlated well for the side step (r2 = 0.58) and side jump (r2 = 0.64). Within subjects, 2D-Cam and 3D data correlated moderately for the side step (r2 = 0.25 (0.19)) and side jump (r2 = 0.36 (0.27)).
  
  
  CONCLUSIONS
  The 2D-Cam method can be used to screen for excessive valgus in elite basketball players, particularly for movements occurring primarily in the frontal plane. This method may also be a useful training evaluation tool when large reductions in dynamic valgus motions are required.
authors.affiliation: Department of Biomedical Engineering, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA. mcleans@bme.ri.ccf.org
authors.forename: S G
authors.initials: SG
authors.lastname: McLean
authors.forename: K
authors.initials: K
authors.lastname: Walker
authors.forename: K R
authors.initials: KR
authors.lastname: Ford
authors.forename: G D
authors.initials: GD
authors.lastname: Myer
authors.forename: T E
authors.initials: TE
authors.lastname: Hewett
authors.forename: A J
authors.initials: AJ
authors.lastname: van den Bogert
mesh_terms: D000328:Adult; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000517:prevention & control*; D001490:Basketball / Q000293:injuries*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007718:Knee Injuries / Q000517:prevention & control*; D007719:Knee Joint / Q000033:anatomy & histology; D008297:Male; D015397:Program Evaluation; D016059:Range of Motion, Articular; D014741:Video Recording / Q000379:methods