Greater Q angle may not be a risk factor of Patellofemoral Pain Syndrome

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 4 m/s (SD 0.2) on a 30 m-runway. Absolute and normalized knee moment and impulse were calculated and correlated with Q-angle. Findings: Negative correlations between Q-angle and the magnitude of peak knee abduction moment (R(2)=0.2444, R = -0.4944, P=0.005) and impulse (R(2)=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 (R(2)=0.1842, R = -0.4292, P=0.016) and impulse (R(2)=0.2304, R = -0.4801, P=0.006) were found. Interpretation: 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. (C) 2010 Elsevier Ltd. All rights reserved.