Effect of feet hyperpronation on pelvic alignment in a standing position.

Hyperpronation may cause malalignment of the lower extremity, frequently leading to structural and functional deficits both in standing and walking. Our aim was to study the effect of induced foot hyperpronation on pelvic and lower limb alignment while standing. Thirty-five healthy subjects were requested to remain in a natural standing position for 20s in four different modes: feet flat on the floor, and on wedges angled at 10 degrees, 15 degrees and 20 degrees, designed to induce hyperpronation. Sequencing was random, repeated three times and captured by eight computerized cameras using the VICON three-dimensional motion analysis system. We found that standing on the wedges at various angles, induced hyperpronation, with 41% to 90% of the changes attributable to the intervention. In addition, a statistically significant increase (paired t-test) in internal shank rotation (p<0.0001), internal hip rotation (p<0.0001) and anterior pelvic tilt (p<0.0001) was identified. A strong correlation was found between segmental alignment in every two consecutive modes at all levels (r=0.612-0.985; p<0.0001). These findings suggest that alignment of the lower extremity up to the pelvic girdle, can be altered, due to forces acting on the foot. Interaction between the foot and pelvis occurs in a kinematic chain reaction manner. Although this study was limited to healthy subjects, clinicians should be aware that when addressing pelvis and lower back dysfunction, foot alignment should be examined as a contributing factor.