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. 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.
Just having an accessory navicular bone is not necessarily a bad thing. Not all people with these accessory bones have symptoms. Symptoms arise when the accessory navicular is overly large or when an injury disrupts the fibrous tissue between the navicular and the accessory navicular. A very large accessory navicular can cause a bump on the instep that rubs on your shoe causing pain.
Possible symptoms of accessory navicular syndrome include redness or swelling in the area of the accessory navicular, and pain that is present around the middle of the foot around the arch. Discomfort is most often present following periods of exercise or prolonged walking or standing. The bone may be somewhat visible on the inside of the foot above the arch. Most symptoms of accessory navicular syndrome first appear in childhood around the time of adolescence as the bones are still growing and developing. For some with an accessory navicular, though, symptoms may not appear until entering adulthood.
Plain x-rays are used to determine the size of the accessory navicular. There are three main types of accessory navicular bones: a small bone embedded within the nearby posterior tibial tendon; a triangular shaped bone connected to the navicular by thick cartilage; and a large prominent navicular tuberosity thought to represent an accessory navicular that has fused to the navicular. If the status of the posterior tibial tendon needs to be assessed or if other problems are suspected, (ex. Navicular stress fracture) it may be necessary to perform an MRI. Although this is not considered routine, an MRI may be helpful in identifying the degree of irritation. An MRI would demonstrate fluid or edema that may accumulate in the bone as a result of the irritation.
Non Surgical Treatment
The foot may be placed in a cast or removable walking boot to allow the affected area to rest and decrease the inflammation. Physical therapy including exercises and treatments to strengthen the muscles, decrease inflammation, and prevent recurrence of the symptoms. Custom orthopedic devices that fit into the shoe providing arch support. Even after successful treatment, symptoms may reappear.
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 What do you do for a strained Achilles tendon? normal foot function.
+ نوشته شده: 1396/5/22 ساعت: ۱۶ توسط:gertrudeco :