title: Greater Q angle may not be a risk factor of patellofemoral pain syndrome.
abstract: BACKGROUND
  A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running.
  
  
  METHODS
  Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8-10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle.
  
  
  RESULTS
  Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R²=0.2444, R=-0.4944, P=0.005) and impulse (R²=0.2563, R=-0.5063, P=0.004) were found. Additionally, negative correlations between Q-angle and the magnitude of weight normalized knee abduction moment (R²=0.1842, R=-0.4292, P=0.016) and impulse (R²=0.2304, R=-0.4801, P=0.006) were found.
  
  
  CONCLUSIONS
  The findings indicate that greater Q-angle, which is actually associated with decreased frontal plane knee abduction moment and impulse during running, may not be a risk factor of Patellofemoral Pain Syndrome.
authors.affiliation: Biomechanics Laboratory, Sport Science Institute, Korea National Sport University, 88-15 Oryun-dong, Songpa-gu, Seoul, Republic of Korea. spark@knsu.ac.kr
authors.forename: Sang-Kyoon
authors.initials: SK
authors.lastname: Park
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Stefanyshyn
mesh_terms: D001696:Biomechanical Phenomena; D001703:Biophysics; D005260:Female; D006801:Humans; D007593:Joint Instability; D007700:Kinetics; D007717:Knee / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D008297:Male; D046788:Patellofemoral Pain Syndrome / Q000503:physiopathology*; D016059:Range of Motion, Articular; D012307:Risk Factors; D012420:Running; D013977:Tibia / Q000503:physiopathology