Defining flatfoot

Pes planus is a term frequently used in describing flatfoot; however, no st udy has objectively defined flatfoot. We evaluated the single leg stance fo otprint of 40 feet in 21 people with no history of foot problems, using pre ssure-sensitive film end a Harris mat. The medial and lateral aspects of th e forefoot, midfoot, and hindfoot were assessed. The midfoot was further an alyzed by dividing the medial midfoot force by the total midfoot force. The mean medial midfoot force/total midfoot force was 11.1% (SD = 6.5%). Pes p lanus was defined as the medial midfoot force/total midfoot force > 24.0% ( mean + 2 SD). A population associated with pes planus (124 feet in 63 patients with Marfa n syndrome) was then evaluated in the same fashion. Although the mean media l midfoot force/total midfoot force was not statistically different (16.0%) , a distinct group of patients (25%) had forces that were outside the range of normal midfoot forces.