FicWad

Overview

An accessory navicular bone is a common finding on many foot x-rays. Most accessory naviculars are asymptomatic. However, in some patients the prominent bone on the inside of foot will create discomfort, which leads to difficulty with shoe fitting. Alternatively, the fibrous union between the navicular bone and the ?extra? accessory part may become irritated and cause discomfort. Diagnosis is completed through physical examination and plain x-rays of the foot. Treatment is usually non-operative, often including a change in shoe wear and activity modification. However, patients that have ongoing symptoms once non-surgical treatments are tried, often consider surgery to remove the prominent accessory navicular and, if necessary, reattach the posterior tibial tendon.





Causes

The syndrome may result from any of the following, previous trauma such as a foot or ankle sprain. Chronic irritation from shoes or other footwear causing friction against the bone. Strain from overuse or excessive activity.


Symptoms

Most people born with this bone begin to experience the symptoms (if at all any) in adolescence. Some may not develop any symptoms until adulthood. The symptoms are a visible abnormal protrusion in the mid-foot, swelling and redness of the protrusion, pain in the mid-foot after performing an activity.


Diagnosis

The foot and ankle are prone to bony ?accessories? which usually have no accompanying symptoms. Accessory navicular syndrome is often diagnosed when an adolescent complains of pain in the foot. Girls are more susceptible than boys, and the condition is usually bilateral, occurring in both feet. Navicular accessory syndrome may be diagnosed when a trauma (foot or ankle sprain) aggravates the bone or tibial tendon, or when there is chronic irritation from footwear or overuse.


Non Surgical Treatment

For less severe symptoms, decreasing or modifying activity, such as avoiding aggravating activities, may suffice. Ice and NSAIDS can be used to help control pain. An arch support or an orthotics may help to stabilize the arch during this time. When rubbing on the bump causes pain, a doughnut pad can be worn. Exercises to increase range of motion and improve movement should still be used.





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.