Abstract
Background: It is important to understand the relative bone position of the hindfoot in order to understand pes planus (flat foot) pathologies as well as to make an accurate diagnosis. The three dimensional (3D) bone position is not yet completely understood. The aim of this study was to quantify and compare the relative bone positions that constitute the hindfoot in the neutral position of the ankle joint in patients with normal feet and pes planus, using 3D computed tomography (CT) reconstruction images.
Methods: CT images were taken of 22 patients with normal feet and 29 patients with pes planus deformity in the neutral position, from which 3D virtual models were made of each mid-hind foot bone. The center of the tibia, the talus, the calcaneus, the navicular bone, and the first metatarsal bone were calculated. The eigenvector of the talus, the calcaneus, and the navicular bone relative to the tibia was calculated. The eigenvector of the calcaneus, the navicular bone, and the first metatarsal bone relative to the talus was also calculated. We compared the 3D relative bone positions between normal feet and pes planus in the neutral position.
Results: The talus in pes planus was more dorsiflexed relative to the tibia as well as more adducted than in the normal foot. The calcaneus was more abducted relative to the tibia as well as more everted in pes planus compared to the normal foot. The first metatarsal bone in pes planus was more dorsiflexed relative to the talus as well as more abducted than in the normal foot. The calcaneus in pes planus was more dorsiflexed relative to the talus, more abducted as well as more everted in comparison to the normal foot. The navicular bone in pes planus was more dorsiflexed relative to the talus.
Conclusions: This study allows for more information to be provided in diagnosing pes planus and selecting more appropriate surgical procedures.
