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Accessory Navicular SyndromeGreg Mack, DPM, FACFAS The accessory navicular is an extra bone or piece of cartilage located on the inner side of the foot just above the arch. It is incorporated within the posterior tibial tendon, which attaches in this area. An accessory navicular is congenital (present at birth) though it is not part of normal bone structure and therefore is not present in most people. Many people who have an accessory navicular often are unaware of the condition if it causes no problems. However, some people with this extra bone develop a painful condition known as accessory navicular syndrome when the bone and/or posterior tibial tendon are aggravated.
Many people with accessory navicular syndrome also have flat feet (fallen arches). Having a flat foot puts more strain on the posterior tibial tendon, which can produce inflammation or irritation of the accessory navicular. Signs you should look for:Adolescence is a common time for the symptoms to first appear. This is a time when bones are maturing and cartilage is developing into bone. Sometimes, however, the symptoms do not occur until adulthood. The signs and symptoms of accessory navicular syndrome include:
How do I as a podiatric physician diagnose?
I often obtain x-rays to confirm the diagnosis. If there is ongoing pain or inflammation, an MRI or other advanced imaging tests may be used to further evaluate the condition. Non-surgical treatment options
If orthotic therapy fails to relieve the symptoms of accessory navicular syndrome, surgery may be appropriate. Surgery may involve removing the accessory bone, reshaping the area and repairing the posterior tibial tendon to improve its function. This extra bone is not needed for normal foot function. It has been my experience if a child experiences these symptoms, removal of this bone is warranted as it can cause a symptomatic flat foot in the future. Removal of the bone before the child is skeletally mature, followed by orthotic therapy, will allow the patient an excellent chance of a normal arch architecture and normal foot function.
Dr. Mack – Foot and Ankle Clinic |
To diagnose accessory navicular syndrome of the foot and ankle I will ask the patient about symptoms and examine the foot, looking for skin irritation or swelling. I press on the bony prominence to assess the area for discomfort. Foot structure, muscle strength, joint motion and the way the patient walks may also be evaluated. 
The goal of non-surgical treatment for accessory navicular syndrome is to relieve the symptoms. Custom molded orthotics are often the preferred non-surgical treatment. The orthotics fit into the patient’s shoes to provide support for the arch and they help play a role in preventing future symptoms.