WHAT IS THE ACCESSORY NAVICULAR?
The accessory navicular is an extra bone or piece of cartilage located on the inner side of the foot just above the arch. It is incorporated within the posterior tibial tendon, which attaches in this area. An accessory navicular is congenital (present at birth). It is not part of normal bone structure and therefore is not present in most people.
WHAT IS ACCESSORY NAVICULAR SYNDROME?
People who have an accessory navicular often are unaware of the condition if it causes no problems. However, some people with this extra bone develop a painful condition known as accessory navicular syndrome when the bone and/or posterior tibial tendon are aggravated. This can result from any of the following: Trauma, as in a foot or ankle sprain, chronic irritation from shoes or other footwear rubbing against the extra bone, and excessive activity or overuse. Many people with accessory navicular syndrome also have flat feet (fallen arches). Having a flat foot puts more strain on the posterior tibial tendon, which can produce inflammation or irritation of the accessory navicular.
The options for treatment range from conservative to surgical. Some of the conservative options are: icing, anti-inflammatory medications, immobilization, physical therapy, calf stretching, orthotics, and ankle bracing. If nonsurgical treatment fails to relieve the symptoms of accessory navicular syndrome, surgery may be appropriate. Surgery may involve removing the accessory bone, reshaping the area and repairing the posterior tibial tendon to improve its function. This extra bone is not needed for normal foot function.