The Effects of Flexible Flat Foot on Lower Limb among Children with the Age of 6-12 Years

In flexible flat foot the medial longitudinal arch eliminates while weight bearing and it has adverse effects on lower extremity chain. The purpose of this study was to investigate the effects of flexible flat foot on lower extremities, especially in hip joint function. In this descriptive cross sectional study, 487 feet of 6-12 years old children evaluated by static foot print. 14 girls and 14 boys with grade 1 and 2 flexible flat foot were selected as case groups and 21 girls and 2 boys with no sign of flat foot were selected as control groups. The following outcomes were measured in 4 study groups: range of active and passive internal and external rotation in sitting and prone position, the strength of internal and external rotator muscles, inter condylar and inter malleollar distance, apparent and true lengths of the lower extremities and Q angle. In girls with flexible flat foot, the internal rotation of the hip was significantly increased compared with that in boy (P<0/05). Similarly, the strength of internal and external rotator muscles was decreased significantly with the amount of 1 degree in manual muscle testing grades (P<0/05). It seems that the flexible flat foot is associated with an increase in internal and external rotation of the hip in early age. This may lead to some mechanical deficits in lower extremity with aging.