Incidence and anatomical variations of accessory navicular bone in patients with foot pain: A retrospective radiographic analysis.

The accessory navicular (AN) is an accessory ossicle anatomically located on the medial side of the foot, proximal to the navicular and continuous with the tibialis posterior tendon. It is occasionally a source of pain and local tenderness. Knowledge of the AN and its morphological variations can help identify the source of a patient's symptoms and prevent misinterpreting them as fractures. Foot radiographs from 1,240 patients who presented in two centers with chronic foot pain, or persistent pain developed after trauma, were retrospectively reviewed to determine the incidence and variations of the AN in relation to gender. The AN was found in 20.9% (259/1240). Among 259 feet with AN, Type 1 was identified in 25.4% (66/259), Type 2 in 42.4% (110/259) (20.0% (52/259) Type 2 A and 22.4% (58/259) Type 2B), and Type 3 in 32.0% (83/259). After 13 patients with incomplete medical records had been excluded, the remaining records showed that foot pain was associated with an AN in 10.6% of patients (26/246). In 1.2% of cases, two additional ossicles were found proximal to the navicular, possibly the result of multiple ossification centers that did not unite at the time of development. Patient symptomatology was related to the presence of an AN in 2% of patients with chronic foot pain. The AN could vary morphologically. Our data can enhance our diagnostic skills in detecting these ossicles. Clin. Anat. 30:436-444, 2017. © 2017 Wiley Periodicals, Inc.