Accessory Navicular Non-Surgical Treatment

Overview
The accessory navicular is an extra piece of bone or cartilage just above the arch on the inside of the foot. It sits next to the navicular tarsal, which gives it its name, where the posterior tibial tendon attaches to the bone before continuing to the underside of the arch. The little bone is a congenital anomaly, you are born with it. If the extra tissue doesn?t cause any problems, you may never know it is there. You can, however, develop the painful condition called accessory navicular syndrome. This occurs when the extra bone or the posterior tibial tendon surrounding it becomes irritated. Trauma from a sprain, friction from footwear, and overuse can all inflame the tissues.



Causes
Like all painful conditions, ANS has a root cause. The cause could be the accessory navicular bone itself producing irritation from shoes or too much activity. Often, however, it is related to injury of one of the structures that attach to the navicular bone. Structures that attach to the navicular bone include abductor hallucis muscle, plantar calcaneonavicular ligament (spring ligament) parts of the deltoid ligament, posterior tibial tendon.

Symptoms
If you develop accessory navicular syndrome, you may experience a throbbing sensation or other types of pain in your midfoot or arch (especially while or right after you use the foot heavily, such as during exercise), and you may notice a bony prominence on the interior of your foot above the arch. This prominence may become inflamed, which means it will likely feel warm to the touch, look red and swollen, and will probably hurt.

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
Many individuals with symptomatic accessory naviculars can be managed successfully without surgery. Standard non-surgical treatment includes shoes that are soft around the inside of the ankle can allow for any excess prominence of bone. Therefore, it is recommended that either shoes with plenty of padding and space in the ankle area are purchased, or pre-owned shoes can be modified by a shoemaker to create extra space in this area. For example, many patients will get their ski boots expanded in the area around the prominence, minimizing irritation. In addition, a shoe with a stiff sole will help disperse force away from the arch of the foot during walking, thereby minimizing the force on the posterior tibial tendon. An off-the-shelf arch support may help decrease the stress applied by the posterior tibial tendon. If necessary, an ankle brace applied to provide more substantial support to the arch may be successful where a simple arch support fails.



Surgical Treatment
The Kidner procedure involves resecting the prominent accessory navicular and ensuring that the posterior tibial tendon is still attached to the bone. Often the prominent bone can simply be shelled out from its position relative to the posterior tibial tendon, which leaves the tendon intact. However, if the tendon is loose and floppy once the extra bone has been removed, suturing or tother is required as a means of attaching it into the remaining navicular bone.