THE VALUES OF Q ANGLE IN CHILDREN ( AN EPIDEMIOLOGY STUDY )

Abstract

Introduction: The values of Q angle in a child’s knee cover a wide range. Frequently its extreme values are responsible for complaints or the appearance of some pathological conditions( e.g. chondromalacia, recurrent dislocation of patella etc).

Material and Methods: The Q angle has been measured in both lower limbs of 1955 children aged 7–12 (1017 boys and 938 girls). Cases of children with a history of previous fractures on lower limbs or major orthopedic or neurological disorders have been excluded. Eighty one per cent of children have had the right foot as their prominent one, the 14.8% of children have had the left foot as their prominent one, and the 4.2% of children have had no difference between their limbs.

Results: For the children aged 7–8, the values of Q angle have been measured to range from 11.30±7.4 degrees in left limb to 11.52±7.4 degrees in right limb in boys, while in girls they ranged from 11.05±7.2 to 11.20±6.9 respectively. For the ages 9–10, the values ranged from 11.30±7.8 degrees in left limb to 11.38±7.2 degrees in right limb in boys, while in girls they ranged from 11.02±7.7 to 11.51±7.1 respectively. For the ages 11–12, the values of Q angle ranged from 11.72±8.8 degrees in left limb to 11.56±8.3 degrees in right limb in boys, while in girls they range from 11.87±8.3 to 12.06±8.4 respectively. There has been no difference between the right and left lower limbs in all ages and both sexes. There has been no difference between the boys and girls in both lower limbs in all ages. As girls are growing up the Q angle is increasing in both lower limbs ( P< 0.01), whereas boys have no difference in their limbs while they are growing up. Children with their prominent right limb have performed increased Q angle in both lower limbs( P< 0.05). Regarding boys, the more Bone Mass Index (BMI) has been increased, the more the Q angle has been decreased ( P< 0.001).

Conclusion: We conclude that in children aged 7–12, the Q angle 1) frequently appears increased values, 2) performs no difference between both lower limbs, and 3) has negative correlation with BMI in boys.