Foot Accessory Navicular Excision

Overview
Sometimes, feet do weird things. For instance, about 10% of the general population?s feet have decided that having an extra bone in the mix is a really great idea. This extra bone (or sometimes a bit of cartilage), is called an accessory navicular. It shows up in a tendon called the posterior tibial tendon (which is a fancy name - but just remember, it helps support the arch of the foot) on the middle of the inside of the foot, just above the arch. This extra little bone is present from birth, so it?s not something that?ll suddenly grow later in life. Now, accessory navicular syndrome is when that extra bone starts causing issues with your shoe-wearing, or even the shape and function of your foot. It?s the syndrome you want to worry about, not necessarily the extra bone itself.



Causes
Accessory navicular syndrome as it is called can result from a number of causes, excess or overuse syndrome as seen in an athlete. Trauma to the foot as in an ankle sprain or direct trauma to the navicular bone. chronic irritation from shoes rubbing against the extra bone, over time, may cause pain. Excessive pronation which strains the attachment of tibialis posterior muscles into the navicular bone. Keep in mind, the larger the actual accessory bone, the greater the chance of it becoming an issue.

Symptoms
Perhaps the most common of the extra bones in the foot, the accessory navicular bone is estimated to be present in 7 to 19 percent of the population. Zadek and Gold maintained that the bone persisted as a distinct, separate bone in 2 percent of the population. Also be aware that the accessory bone normally fuses completely or incompletely to the navicular. It is this incomplete fusion which allows for micromotion, which, in turn, may cause degenerative changes that can also contribute to the pain.

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
Most children?s symptoms are improved or resolved by taking a break from activities that irritate their feet. Shoe inserts that pad the accessory navicular area are also helpful. If your child?s symptoms do not improve, your physician may recommend a below-the-knee cast or walking boot. Surgery is rarely needed.



Surgical Treatment
Surgery may be an option if non-surgical treatment does not decrease the symptoms of accessory navicular syndrome. Since this bone is not needed for the foot to function normally, Your surgeon may remove the accessory navicular, reshape the area, and repair the posterior tibial tendon for improved function.