Accessory Navicular Syndrome in Oxnard & Northridge
The accessory navicular (os navicularum or os tibiale externum) 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.
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
- 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.
Signs and Symptoms of Accessory Navicular Syndrome:
Adolescence is a common time for the symptoms to first appear. This is a time when bones are maturing and cartilage is developing into bone. Sometimes, however, the symptoms do not occur until adulthood. The signs and symptoms of accessory navicular syndrome include:
- A visible bony prominence on the midfoot (the inner side of the foot, just above the arch)
- Redness and swelling of the bony prominence
- Vague pain or throbbing in the midfoot and arch, usually occurring during or after periods of activity
When is Surgery Needed?
If non-surgical 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.
