Pain After Accessory Navicular Surgery

Overview
As many as 14% of people have an ?accessory? or extra bone or piece of cartilage on the inner side of the foot. An accessory navicular is an inborn condition that affects only a minority of the population. It is not part of normal bone structure and therefore is not present in most people. It may be found when the foot is x-rayed for other reasons, or when irritation develops. Patients may not be aware of it until a change in their activity, growth spurt or new footwear creates friction. Most cases of accessory navicular syndrome are treated conservatively.



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
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
Initial treatment is conservative. With the first episode of symptoms, a medial heel wedge, anti-inflammatories, and physical therapy can be helpful. If very painful, a cast or boot may be needed for a short period time before the wedge and physical therapy can be initiated. Very rarely is a steroid injection warranted or recommended. As the pain improves, patients can resume activities. For a minority of patients, an arch support or custom orthotic can help to take some of the extra pressure off of the accessory navicular and the posterior tibial tendon.



Surgical Treatment
Once the navicular inflammation has lessened it is not necessary to perform surgery unless the foot becomes progressively flatter or continues to be painful. For these children, surgery can completely correct the problem by removing the accessory navicular bone and tightening up the posterior tibial tendon that attaches to the navicular bone. The strength of this tendon is integral to the success of this surgery as well as the arch of the foot. Following surgery the child is able to begin walking on the foot (in a cast) at approximately two weeks. The cast is worn for an additional four weeks. A small soft ankle support brace is then put into the shoe and worn with activities and exercise for a further two months.