The os trigonum is an extra bone that oftentimes forms at the back part of the ankle bone. It is linked to the ankle bone by a fibrous band and usually present at birth in one or both feet.
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The extra bone becomes evident during the teenage years when one region of the ankle bone does not fuse with the entire bone, resulting to a small extra bone. Only a few individuals develop this accessory bone.
Oftentimes, many individuals are not aware that they have the condition if it does not trigger any issues. Nevertheless, some with the extra bone experience pain which is called os trigonum syndrome.
What is the cause?
Os trigonum syndrome is generally brought about by an injury such as an ankle sprain. It can also be caused by repetitive downward pointing of the toes which is common in ballet, soccer and other athletes.
What are the indications?
The usual indications of os trigonum syndrome might include the following:
- Deep, aching pain or discomfort in the back part of the ankle, usually when pushing off on the big toe or when the toes are pointed downward
- Swelling in the back region of the ankle
- Tenderness of the area when touched
Management of os trigonum syndrome
The management of os trigonum syndrome is aimed on relieving the symptoms that is often achieved using treatment options such as:
- Adequate rest by staying off the damaged foot to allow the inflammation to settle
- Immobilization using a walking boot can help limit movement of the ankle as well as allow healing.
- Application of an ice pack can help reduce the swelling.
- Oral medications such as non-steroidal anti-inflammatory drugs (NSAIDs) can help reduce the inflammation and pain
- Cortisone injections are administered directly into the area to reduce the pain and inflammation
In most cases, the symptoms generally settle with conservative measures. Nevertheless, surgery is needed to alleviate the symptoms. Surgery involves the removal of the os trigonum since it is not required for normal functioning of the foot.