Many people are unaware they have this congenital condition because it causes no problems. However, some people develop Accessory Navicular Syndrome when the bone and/or posterior tibial tendon are aggravated as a result of trauma, chronic irritation from poor fitting footwear, or excessive activity or over use.
Many people with accessory navicular syndrome also have flat feet (fallen arches), which puts more strain on the posterior tibial tendon, causing inflammation or irritation to the accessory navicular.
Symptoms of this condition typically first appear in adolescence, when bones are maturing and cartilage is turning into bone. Some people don’t experience the following symptoms until adulthood:
• A visible bony prominence on the inner side of the foot, just above the arch (midfoot).
• Redness and swelling of the bony prominence.
• Vague pain or throbbing in the midfoot and arch, usually during or after a period of activity.
Diagnosis of Accessory Navicular Syndrome is made through evaluation of a patient’s symptoms and examination of the foot structure, muscle strength, joint motion and the way the patient walks. X-rays can confirm the diagnosis. In some cases, an MRI will be ordered to further evaluate the condition.
The following non-surgical treatments can relieve the symptoms of Accessory Navicular Syndrome.
• Immobilization with casting or removable walking boot allows the affected area to rest and alleviate the inflammation.
• Ice to reduce swelling.
• Oral non-steroidal anti-inflammatory drugs such as ibuprofen may be prescribed.
• In some cases, steroid injections may be used in combination with immobilization to reduce pain and inflammation.
• Physical therapy may be prescribed, including exercises and treatments to strengthen the muscles and decrease inflammation. The exercises may also help prevent recurrence of the symptoms.
Even after successful treatment, the symptoms of Accessory Navicular Syndrome sometimes recur. When this happens, nonsurgical approaches are usually repeated.
If nonsurgical treatment fails to relieve the symptoms, 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.