Type Ii Accessory Navicular Bone

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
Most of the time, this condition is asymptomatic and people may live their whole lives unaware that they even have this extra bone. The main reason the accessory navicular bone becomes problematic is when pain occurs. There is no need for intervention if there is no pain. The accessory navicular bone is easily felt in the medial arch because it forms a bony prominence there. Pain may occur if the accessory bone is overly large causing this bump on the instep to rub against footwear.

Symptoms
Many people have accessory (?extra?) naviculars (figure 1) - a prominent extra bone extending from the navicular bone. Most accessory naviculars are completely asymptomatic. However, some individuals will develop pain on the inside of their midfoot. Pain may occur from the pressure of the shoe ware against the prominence, irritating either the bone itself or the fibrous junction where the accessory bone meets the regular navicular. Alternatively, the fibrous junction or interface may become painful as a result of tension applied by the posterior tibial tendon through its connection or insertion at that site. Often, individuals will be asymptomatic for years, however, a new pair of shoes or a change in their activity level can cause symptoms. The accessory navicular itself typically develops during adolescence, when the two areas of the navicular bone fail to fuse together.

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
Most children?s symptoms are improved or resolved by taking a break from activities that irritate their feet. Shoe inserts that pad the accessory navicular area are also helpful. If your child?s symptoms do not improve, your physician may recommend a below-the-knee cast or walking boot. Surgery is rarely needed.



Surgical Treatment
After the anesthesia is administered you will be heavily sedated and placed on your stomach. Surgeons will place a tourniquet around your thigh and an incision will be made on the inside of the foot. The posterior tibial tendon will be moved as necessary and the accessory navicular will be removed. Surgeons will repair the posterior tibial tendon with sutures or suture anchors, and the wound will be closed. A splint will be placed on the foot for stabilization and immobilization. You will be permitted to leave the surgical center once you have been cleared by the anesthesiologist. Plan ahead to have a friend or family member take your prescription to a pharmacy to pick up your post-op medication. Use narcotic pain medications before bed or if numbness in your foot begins to dull. Schedule a post-op visit for 4 weeks after the procedure.