Type Ii Accessory Navicular Bone

Overview
There are three different types of accessory navicular. This extra cartilage, which is turned into bone, is found attached to the posterior tibial tendon, just medial (inside) the navicular bone. The accessory navicular can affect the insertion of the posterior tibial tendon. This tendon has a job of keeping your foot aligned and helping to maintain an arch. The accessory navicular can be associated with a normal foot posture and alignment, or sometime with a flat (pes planus) foot.



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
Symptoms of this syndrome would include redness, swelling and tenderness over the navicular bone. The navicular bone is located on the inside of the foot approximately midway between the ankle bone and big toe joint. It will tend to be worse after activity and can be aggravated by those that wear very dressy shoes as opposed to casual shoes like sneakers. In other words, the flatter or less supportive the shoe, the greater the chance for 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
If symptoms have been aggravated by an increase in activity level, backing off on activities in the short term can be helpful. The foot is subject to a lot of repetitive loading during walking, and therefore minimizing this force will often help symptoms to settle. After symptoms have settled, the activity level can then be gradually increased.



Surgical Treatment
Surgical treatment of the accessory navicular syndrome with simple excision has the advantages of less invasive to the posterior tibial tenden and the medial longitudinal arch of the foot, shorter time of immobilization of the foot and stay in hospital, small incision and good clinical results. This procedure is one of the best selective treatments for the accessory navicular syndrome, especially for the patients without flatfoot deformity and old sprain injury.