What Is That Extra Bone In My Foot?

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.
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

To diagnose accessory navicular syndrome, the foot and ankle surgeon will ask about symptoms and examine the foot, looking for skin irritation or swelling. The doctor may press on the bony prominence to assess the area for discomfort. Foot structure, muscle strength, joint motion, and the way the patient walks may also be evaluated.
X-rays are usually ordered to confirm the diagnosis. If there is ongoing pain or inflammation, an MRI or other advanced imaging tests may be used to further evaluation the condition.
The goal of non-surgical treatment for accessory navicular syndrome is to relieve the symptoms. The following may be used:

• Immobilization. Placing the foot in a cast or removable walking boot allows the affected area to rest and decreases the inflammation.
• Ice. To reduce swelling, a bag of ice covered with a thin towel is applied to the affected area. Do not put ice directly on the skin.
• Medications. Oral nonsteroidal anti-inflammatory drugs (NSAIDS), such as ibuprofen, may be prescribed. In some cases, oral or injected steroid medications may be used in combination with immobilization to reduce pain and inflammation. 
• Physical therapy. Physical therapy may be prescribed, including exercises and treatments to strengthen the muscles and decrease inflammation. The exercises may also help prevent recurrence of the symptoms.
• Orthotic devices. Custom orthotic devices that fit into the shoe provide support for the arch, and may play a role in preventing future symptoms. 

Even after successful treatment, the symptoms of accessory navicular syndrome sometimes reappear. When this happens, non-surgical approaches are usually repeated.
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.
Ayman M. Latif, DPM
Connecticut Foot Care Centers
Foot Deformity Doctor in CT
Podiatrist in Glastonbury and Middletown, CT
Visit our website, like our page on Facebook, and follow our tweets on Twitter. 

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What is Os Trigonum Syndrome?

The os trigonum is an extra (accessory) bone that sometimes develops behind the ankle bone (talus). It is connected to the talus by a fibrous band. The presence of an os trigonum in one or both feet is congenital (present at birth). It becomes evident during adolescence when one area of the talus does not fuse with the rest of the bone, creating a small extra bone. Only a small number of people have this extra bone.
Often, people don't know they have an os trigonum if it hasn't caused any problems. However, some people with this extra bone develop a painful condition known as os trigonum syndrome.

Os trigonum syndrome is usually triggered by an injury, such as an ankle sprain. The syndrome is also frequently caused by repeated downward pointing of the toes, which is common among ballet dancers, soccer players, and other athletes.
For the person who has an os trigonum, pointing the toes downward can result in a "nutcracker injury". Like an almond in a nutcracker, the os trigonum is crunched between the ankle and heel bones. As the os trigonum pulls loose, the tissue connecting it to the talus is stretched or torn and the area becomes inflamed.
The signs and symptoms of os trigonum syndrome may include:

• Deep, aching pain in the back of the ankle, occurring mostly when pushing off on the big toe (as in walking) or when pointing the toes downward
• Tenderness in the area when touched
• Swelling in the back of the ankle

Os trigonum syndrome can mimic other conditions such as Achilles tendon injury, ankle sprain, or talus fracture. Diagnosis of os trigonum syndrome begins with questions from the doctor about the development of the symptoms. After the foot and ankle are examined, x-rays or other imaging tests are often ordered to assist in making the diagnosis.
Relief of symptoms is often achieved through treatments that can include a combination of the following:

• Rest. It is important to stay off the injured foot to let the inflammation subside.
• Immobilization. Often a walking boot is used to restrict ankle motion and allow the injured tissue to heal.
• Ice. Swelling is decreased by applying a bag of ice covered with a thin towel to the affected area. Do not put ice directly against the skin. 
• Oral medication. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be helpful in reducing the pain and inflammation.
• Injections. Sometimes cortisone is injected into the area to reduce the inflammation and pain. 

Most patients' symptoms improve with non-surgical treatment. However, in some patients, surgery may be required to relieve the symptoms. Surgery typically involves removal of the os trigonum, as this extra bone is not necessary for normal foot function.
Ayman M. Latif, DPM
Connecticut Foot Care Centers
Foot Deformity Doctor in CT
Podiatrist in Glastonbury and Middletown, CT
Visit our website, like our page on Facebook, and follow our tweets on Twitter. 

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• What Is That Extra Bone In My Foot?

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• Why Won't My Foot Move? Is It Tarsal Coalition?

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