Foot Accessory Navicular Excision

Overview
Everyone has one navicular bone: one of the small bones of the foot. A small number of people have a second small navicular bone or piece of cartilage located on the inside of the foot just above the arch: both are simply called an "accessary navicular bone." It is located within the posterior tibial tendon which attaches in this area. It is easy to see as a "bump." Most that have it never have pain. If they get pain, we call it: "Accessary navicular bone syndrome."



Causes
An injury to the fibrous tissue connecting the two bones can cause something similar to a fracture. The injury allows movement to occur between the navicular and the accessory bone and is thought to be the cause of pain. The fibrous tissue is prone to poor healing and may continue to cause pain. Because the posterior tibial tendon attaches to the accessory navicular, it constantly pulls on the bone, creating even more motion between the fragments with each step.

Symptoms
Most people with an accessory navicular do not have symptoms because the bone is so small that it causes no harm, or only develop symptoms after a trauma such as a break or sprain. When symptoms are present they could be a visible bony prominence, pain and throbbing, inflammation and redness, and flat feet.

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
The goal of non-surgical treatment for accessory navicular syndrome is to relieve the symptoms. The following may be used. Immobilization. Placing the foot in a cast or removable walking boot allows the affected area to rest and decreases the inflammation. Ice. To reduce swelling, a bag of ice covered with a thin towel is applied to the affected area. Do not put ice directly on the skin. Medications. Oral nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be prescribed. In some cases, oral or injected steroid medications may be used in combination with immobilization to reduce pain and inflammation. Physical therapy. Physical therapy may be prescribed, including exercises and treatments to strengthen the muscles and decrease inflammation. The exercises may also help prevent recurrence of the symptoms. Orthotic devices. Custom orthotic devices that fit into the shoe provide support for the arch, and may play a role in preventing future symptoms. Even after successful treatment, the symptoms of accessory navicular syndrome sometimes reappear. When this happens, non-surgical approaches are usually repeated.



Surgical Treatment
In the original Kidner procedure, the entire posterior tibial tendon was released from the navicular and then rerouted through a drill hole placed through the navicular. The original Kidner procedure is now rarely used as a means of treating an isolated accessory navicular. Instead, a modification of the Kidner procedure has become more commonplace. The modified Kidner procedure consists of carefully removing the accessory and anchoring the posterior tibial tendon to the surface of the navicular where the accessory was removed. The repair may be done by passing a suture through the tendon and then through drill holes in the navicular, or by using a suture anchor.