Accessory Navicular Syndrome

Accessory navicular syndrome is a painful condition caused by the presence of a small extra bone or piece of cartilage on the inside of the foot. The extra bone is commonly located just above the arch of the foot. The extra bone is called an accessory navicular. An accessory navicular is a congenital defect. This extra bone does not ossify until about age nine. For about half of those born with an accessory navicular, the extra bone will fuse with the normal navicular bone of the foot.

About ten percent of the population has an accessory navicular. For most people with the extra bone, it never poses any problems. Therefore, they may never even know they have an extra bone. Some people with this extra bone develop accessory navicular syndrome.

This condition causes pain and may cause redness and swelling. The development of accessory navicular syndrome occurs when the bone or tendon becomes aggravated. This can happen due to an injury, overuse, or irritation from footwear.

To diagnose this condition, the physician will manipulate the foot and feel for the extra bone. An x-ray will show the presence of an accessory navicular. The doctor may suggest the use of anti-inflammatory pain relievers. Applying ice to the area may help reduce swelling. The doctor may use of a cast or walking boot to immobilize the area in order to allow it to heal without further aggravation. Physical therapy may be used to strengthen the muscles. If non-invasive methods fail to provide relief, the extra bone may be surgically removed.

Children with flat feet are at risk for accessory navicular syndrome. After non-surgical treatment, the doctor is likely to prescribe the use of orthotics to support the arch and help prevent future occurrences of accessory navicular syndrome. Though adolescence is usually the time when accessory navicular syndrome develops, it can occur in childhood and adulthood.