Accessory navicular syndrome

Case contributed by Dr Justin G Peacock

Presentation

Military trainee with ongoing bilateral medial midfoot pain with walking or running. Variable medial foot tenderness with palpation.

Patient Data

Age: 20 years
Gender: Female

After initial X-ray imaging of the most painful right foot, bone scintigraphy was performed to assess for a stress fracture.

Nuclear medicine

No stress fracture is identified on these images. Our institution uses the intensity of the ASIS radiotracer uptake when assessing for stress fractures. Mild focal uptake in the region of the bilateral medial midfoot, overlying the expected navicular/accessory navicular bone.

X-ray

No acute injury or stress fracture is identified on these images. An incidental type 2 os navicularis is seen.

Case Discussion

There are three types of accessory navicular, with the most symptomatic being type 2 accessory navicular bones, because they are often connected to the navicular via cartilage. Type 1 is separate from the navicular and type 3 is a prominent navicular tuberosity. The close connection of the type 2 accessory navicular can lead to osseous inflammation with exercise. Posterior tibial inflammation and injury has also been observed. The inflammation can be seen on MRI or on bone scan as in this case.

Although only right foot X-rays were obtained for this patient, it is likely that the patient has bilateral type 2 accessory navicular bones, given the uptake seen on the bone scan. 

For this patient, rest was recommended and follow-up evaluation demonstrated a resolution of the pain.

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