Will Accessory Navicular Syndrome Always Warrant Surgery

Overview
An accessory navicular is defined as an extra bone in the foot, and oftentimes it causes moderate to severe discomfort. Depending on the severity, your doctor may recommend a non-surgical treatment to alleviate the pain, or surgery if treatment doesn?t decrease symptoms.



Causes
It is commonly believed that the posterior tibial tendon loses its vector of pull to heighten the arch. As the posterior muscle contracts, the tendon is no longer pulling straight up on the navicular but must course around the prominence of bone and first pull medially before pulling upward. In addition, the enlarged bones may irritate and damage the insertional area of the posterior tibial tendon, making it less functional. Therefore, the presence of the accessory navicular bone does contribute to posterior tibial dysfunction.

Symptoms
It?s common for any symptoms to present during adolescence, when bones are maturing, though problems may not occur until adulthood. You may notice a bony prominence on the inner side of the midfoot. There may or may not be redness and swelling around this bump, especially if it rubs against footwear. You may be prone to blisters or sores in the area. Pain generally involves a vague ache or throbbing in the midfoot and arch as well, especially when you?re active. Many people with this syndrome develop flat feet, too, which can create additional strain in the foot.

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.