The accessory navicular bone exists as an extra bone or piece of cartilage located on the inner side of the foot just above the arch. Some people with this bone develop a painful condition known as accessory navicular syndrome when an injury aggravates the bone and/or posterior tibial tendon.

People with an accessory navicular bone tend to only notice the condition if it causes problems. However, some patients develop a painful condition known as Accessory Navicular Syndrome when the bone or posterior tibial tendon are aggravated. This may result from:

  • Trauma, such as a foot or ankle sprain
  • Chronic irritation from poorly fitted shoes
  • Excessive activity or overuse of the foot

Many patients with accessory navicular syndrome will also present with flat feet. Fallen Arches put more strain on the posterior tibial tendon, which produces inflammation and irritation of the accessory navicular.

Symptoms of Accessory Navicular Syndrome

Symptoms of Accessory Navicular Syndrome commonly appear during adolescence, the time when bones mature and cartilage develops into bone tissue. However, sometimes the symptoms do not appear until adulthood. The symptoms of accessory navicular syndrome include:

  • A bony bump on the midfoot (the inner side of the foot, just above the arch)
  • Swelling and redness of the bony prominence
  • Vague throbbing and pain in the arch of the midfoot, usually during or after periods of activity

If conservative treatment fails to relieve the symptoms of Accessory Navicular Syndrome, Patients may require surgery. Surgery may involve removal of the accessory bone, reshaping the area and repairing the posterior tibial tendon to help improve function.