Demographic, physical, and radiographic factors associated with functional flatfoot deformity.

In 1 of our previous studies, the occurrence of self-reported flatfoot was associated with self-reported increased age, male gender, Asian and African American races, veteran status, poor health, increased body mass index, callus, bunion, hammertoe, and arthritis. However, we had to rely on survey data to identify these risk factors, and the accuracy of the survey results was unknown. Therefore, we decided to identify the risk factors associated with flatfeet using objectively and more accurately measured data. A total of 94 patients were enrolled in the present study. The demographic data and physical and radiographic examination results were recorded by the investigators in the clinic. The data were then analyzed to identify the factors unique to flatfoot, measured and defined using a plantar pressure measurement system during natural gait. We learned that a painful tibialis posterior tendon was associated with flatfoot. The calcaneal inclination angle was also decreased in the flatfoot group. The talar declination, intermetatarsal, hallux abductus, and calcaneal cuboid angles, and static calcaneal stance eversion were elevated in the flatfoot group compared with the non-flatfoot group. Systematic evaluation of these associated factors will help in the understanding of the functional status of the flatfoot deformity.