Foot Accessory Navicular Excision

Overview
For most people with an accessory navicular, the extra bone does not cause any problems and most are unaware of its presence. But certain activities or circumstances may cause the extra bone or the tibialis posterior tendon that contains it to grow irritated. This is called accessory navicular syndrome, and its possible causes include sprains, overuse, or wearing shoes that constantly rub against the bone. Individuals who have a collapsed arch (commonly known as flat feet) may be at greater risk of accessory navicular syndrome, assuming they have the extra bone, because of the added daily trauma placed on the tibialis posterior tendon.



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
What precipitates the pain? It will usually be caused by rubbing of the skate or other footwear against the prominence. You?ll commonly see blisters or a red irritated area. Other symptoms to look for, especially when you?re treating an older child or adult, include an area of pain along the posterior tibial tendon of the arch and fatigue of the legs. Typically, these patients are not able to participate in sports for a lengthy period of time or you?ll hear them complain of pain and/or soreness after extended activities. Most individuals with a prominent navicular area will have tried accommodating this area with a doughnut pad or adjustments to their skate.

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
A combination of the following non-surgical treatments may be used to relieve the symptoms of accessory navicular syndrome. Immobilizing the foot with a cast or a removable walking boot allows the foot to rest and reduces inflammation. Applying ice to the affected area is an effective way to reduce swelling and inflammation. Wrap a bag of ice with a thin towel and apply for intervals of 15 to 20 minutes. Never put ice directly on the skin. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) including aspirin or ibuprofen might be prescribed. Sometimes, a combination of immobilization and oral or injected corticosteroid medications may reduce pain and inflammation. Physical therapy may be prescribed to include exercises and treatments that increase muscle strength, decrease inflammation and help prevent the recurrence of symptoms. Custom orthotic devices worn in the shoe provide arch support and may prevent future symptoms from developing. The symptoms of this syndrome may reappear even after successful treatment. If so, non-surgical treatments are often repeated.



Surgical Treatment
If non-operative treatment fails to relieve the patient’s symptoms, surgical intervention may be warranted. The standard operative treatment of an accessory navicular is a Kidner procedure. However, if surgery is undertaken it is important that it address the underlying source of the patients pain.