Accessory Navicular is Associated With Wider and More Prominent Navicular Bone in Pediatric Patients by Radiographic Measurement.

Background: Accessory navicular (AN) is a common anatomic variant that is known to cause medial foot pain. Surgery may be required for excision if conservative measures fail. Often, the medial border of the navicular is excised in addition to the AN during surgery. The purpose of this radiographic study is to determine if the presence of an AN is associated with a wider or more prominent navicular in pediatric patients compared with normal controls.

Methods: This study included pediatric patients who received an initial plain anteroposterior foot radiograph between January 1, 2004 and December 31, 2012 and were between the ages of 10 and 20 years. Feet with an AN were compared with those without, while controlling for age. Male and female patients were analyzed independently. Feet with fractures, deformities, or previous surgeries were excluded. Radiographic measurements included the navicular width and the protrusion of the navicular bone medially.

Results: A total of 592 feet were included. An AN was identified in 73 feet. Male patients were analyzed separately from females. Cases with 1 AN bone had similar-sized native navicular bones in the contralateral normal foot compared with controls with 2 normal feet (P>0.05). The presence of an AN was associated with a larger navicular width (male: P=0.02, female: P=0.02) and a larger medial protrusion percent (male: P<0.01, female: P<0.01). Age was controlled for.

Conclusion: On radiographic examination, feet with an AN had wider native navicular bones that protruded more medially than feet without an AN.

Level Of Evidence: Level IV-diagnostic.