Does Accessory Navicular Syndrome Require Surgery

Overview
When there is injury to the muscle, fibrous tissue, or soft tissue of the navicular and the accessory navicular bones, symptoms will arise. This injury allows excessive movement between the bones. Fibrous tissue, ligaments and tendons have poor blood supply and are prone to poor healing. Often, this extra navicular bone lies near or attaches to the posterior tibial tendon. (See figure.) When the posterior tibial muscle contracts with movements such as foot inversion or plantar flexion, the posterior tendon moves and the accessory navicular bone moves. This can cause severe pain in those with Accessory Navicular Syndrome. It can become disabling to patients because the posterior tibial tendon attached to the navicular bone is responsible for supporting the medial arch during standing, walking and running. Activities which most of us do daily!



Causes
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. This can result from any of the following. Trauma, as in a foot or ankle sprain. Chronic irritation from shoes or other footwear rubbing against the extra bone. Excessive activity or overuse.

Symptoms
This painful condition is called accessory navicular syndrome. Accessory navicular syndrome (ANS) can cause significant pain in the mid-foot and arch, especially with activity. Redness and swelling may develop over this bony prominence, as well as extreme sensitivity to pressure. Sometimes people may be unable to wear shoes because the area is too sensitive.

Diagnosis
To diagnose accessory navicular syndrome, medical staff ask about the patient?s activities and symptoms. They will examine the foot for irritation or swelling. Medical staff evaluate the bone structure, muscle, joint motion, and the patient?s gait. X-rays can usually confirm the diagnosis. MRI or other imaging tests may be used to determine any irritation or damage to soft-tissue structures such as tendons or ligaments. Because navicular accessory bone irritation can lead to bunions, heel spurs and plantar fasciitis, it?s important to seek treatment.

Non Surgical Treatment
For less severe symptoms, decreasing or modifying activity, such as avoiding aggravating activities, may suffice. Ice and NSAIDS can be used to help control pain. An arch support or an orthotics may help to stabilize the arch during this time. When rubbing on the bump causes pain, a doughnut pad can be worn. Exercises to increase range of motion and improve movement should still be used.



Surgical Treatment
In my experience, the Modified Kidner procedure is one of the most reliable operations for reducing arch pain associated with an accessory navicular bone (a.k.a. os tibial externum). You can also use this procedure to treat a prominence at the inner aspect of the arch, which has been caused by an enlarged navicular bone. The most common patients to visit our office with these problems are between the ages of 8 and 15 and are involved in activities like ice skating, ballet and soccer.