The Relationship Between Accessory Navicular and Flat Foot: A Radiologic Study

The aim of this study was to investigate the relationship between accessory navicular (AN) and flat foot and to evaluate the association between flat foot and the symptoms of patients with AN.

We enrolled 196 patients with painful or asymptomatic AN in this study. Patients who were older than 18 years or who had no weight-bearing radiographs of the feet were not included. Another 46 normal participants were used as a control group. The AN group was divided into 3 subgroups: a group with asymptomatic AN; a symptomatic group that had not undergone excision; and a symptomatic group that had undergone surgery. Seven radiographic indices were measured including calcaneal pitch angle, tibiocalcaneal angle, talocalcaneal angle, naviculocuboid overlap, talonavicular coverage angle, lateral talo-first metatarsal angle, and AP talo-first metatarsal angle. Groups were compared regarding age, sex, presence of pain at the time of surgery, and radiographic parameters.

The calcaneal pitch angle in the AN group was significantly smaller than that of controls (P=0.004). Naviculocuboid overlap (P=0.001), talonavicular coverage angle (P<0.001), lateral talo-first metatarsal angle (P=0.014), and AP talo-first metatarsal angle (P<0.001) were significantly larger in the AN group than in controls. No significant radiologic differences were seen between patients with symptomatic and asymptomatic AN. No significant radiographic differences were found between the groups of patients who had and who had not had bone excised.

AN associated with radiographic parameters felt to be representative of a flat foot; however, the degree of flat foot was not associated with the development and severity of symptoms in patients with AN.