Extra Bone In Foot Accessory Navicular

Overview
Accessary bone syndrome affects overpronators because of irritation in this area. Improper fitting shoes can also irritate the area. When pain becomes such that it changes running form or becomes intolerable, something needs to be done. Surgery alone without addressing causative factors is useless. Pain returns and new cartilage returns in the tendon, and the inflammation causes pain.



Causes
An accessory navicular develops as a result of a congenital anomaly and is found more often in women. If the bone is large, it may rub against a shoe, causing pain. Because of its location, the posterior tibial tendon may pull on the bone during walking or running, causing the fibrous tissue that connects the accessory navicular to the navicular to tear and become inflamed.

Symptoms
The majority of people with an accessory navicular experience no symptoms, since, for the most part, the little extra bone simply isn?t large enough to cause problems. Unfortunately, some people lose on ?accessory navicular roulette,? and the bone begins to mess things up with the foot. These problems usually show up sometime in adolescence, when bones and cartilage in the body are settling into their final shapes (although occasionally people make it all the way through childhood, only to start experiencing discomfort and pain in adulthood).

Diagnosis
Diagnosis is fairly simple based on an examination by your doctor. He or she will palpate the navicular bone, and based on the location of pain will suspect an accessory navicular. The doctor will also observe your gait to see if you are flatfooted. At this point an x-ray will make the definitive diagnosis. Other causes of pain in the same area of the foot would include a fracture of the navicular bone or possibly tendonitis or even a partial tear of the tibialis posterior tendon that inserts into the navicular. In these cases there is usually a history of trauma. People with a naturally "large" navicular bone may also develop a bursitis due to chronic shoe pressure.

Non Surgical Treatment
Aside from surgery, there are a few options for handling an accessory navicular bone that has become symptomatic. This includes immobilization, icing, medicating, physical therapy, and orthotic devices. Immobilizing involves placing the foot and ankle in a cast or crooked toes removable walking boot. This alleviates stressors on the foot and can decrease inflammation. Icing will help reduce swelling and inflammation. Medication involves usage of nonsteroidal anti-inflammatory drugs, or steroids (taken orally or injected) to decrease inflammation. Physical therapy can be prescribed in order to strengthen the muscles and help decrease inflammation. Physical therapy can also help prevent the symptoms from returning. Orthotic devices (arch support devices that fit in a shoe) can help prevent future symptoms. Occasionally, the orthotic device will dig into the edge of the accessory navicular and cause discomfort. For this reason, the orthotic devices made for the patient should be carefully constructed.



Surgical Treatment
The original procedure advocated by Kidner involved shelling out of the accessory navicular bone from within the insertional area of the posterior tibial tendon and rerouting this tendon under the navicular bone in hopes of restoring a normal pull of this tendon. When treating younger children, history has shown us that simply shelling out of the accessory navicular bone from within the tendon and remodeling the tuberosity of the navicular bone can give you satisfactory results.
In general, you want to reserve advancement of the posterior tibial tendon for adults or those who have a more significant flatfoot deformity. You may also use this approach after determining that quality custom orthotics are only resulting in a slight decrease of symptoms.