title: Relationship between knee joint laxity and knee joint mechanics during the menstrual cycle.
abstract: BACKGROUND
  An increase in knee laxity during the menstrual cycle may increase the risk of anterior cruciate ligament injury.
  
  
  OBJECTIVE
  To investigate whether changing knee laxity during the menstrual cycle correlates with changing knee joint loads in a cutting manoeuvre.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Laboratory testing.
  
  
  METHODS
  25 healthy women, with a normal menstrual cycle, no history of oral contraceptive use, and no previous knee injury
  
  
  METHODS
  Serum hormone concentrations were assessed and knee joint laxity at a load of 89 N was measured during the follicular, ovulation and luteal phases. Participants performed 10 trials of a cutting manoeuvre to quantify knee joint mechanics at each test session.
  
  
  METHODS
  Knee joint laxity (mm), peak knee angle ( degrees ) and knee joint moment (Nm) and knee joint impulse (Nms).
  
  
  RESULTS
  Increased knee laxity was observed during ovulation compared with the luteal phase, but no significant changes in knee mechanics corresponding to menstrual phases were found. A positive correlation was found between changes in knee laxity and changes in knee joint loads (Deltamoment or Deltaimpulse) from the follicular phase to ovulation, and from ovulation to the luteal phase (p<0.05). Women in whom knee laxity increased showed increased knee loads, and those in whom knee laxity decreased showed decreased knee loads during the menstrual cycle.
  
  
  CONCLUSIONS
  Knee laxity correlates positively with knee joint loads, and increased knee laxity during the menstrual cycle may be a potential risk factor for anterior cruciate ligament injuries in certain women during sports activity.
authors: Human Performance Laboratory, University of Calgary, 2500 University Drive, NW, Calgary, Alberta T2N 1N4, Canada.
authors: S-K
authors: SK
authors: Park
authors: D J
authors: DJ
authors: Stefanyshyn
authors: B
authors: B
authors: Ramage
authors: D A
authors: DA
authors: Hart
authors: J L
authors: JL
authors: Ronsky
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology; D000070598:Anterior Cruciate Ligament Injuries; D001265:Athletic Injuries / Q000209:etiology* / Q000503:physiopathology; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005498:Follicular Phase / Q000502:physiology; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology; D007718:Knee Injuries / Q000209:etiology* / Q000503:physiopathology; D008183:Luteal Phase / Q000502:physiology; D008597:Menstrual Cycle / Q000502:physiology*; D010060:Ovulation / Q000502:physiology; D016059:Range of Motion, Articular; D012307:Risk Factors; D012737:Sex Factors; D055815:Young Adult