Os Trigonum Syndrome

What is the Os Trigonum?

The Os Trigonum in an extra bone that can develop behind the ankle joint behind the talus. This accessory bone is connected to the talus by a fibrous band and is present at birth. It can be present in either one or both ankles. 

What is Os Trigonum Syndrome?

Most people with an os trigonum do not develop pain unless that play a sport with repetitive downward ankle pointing such as ballet or soccer or they have an ankle injury. The repetitive downward pointing of the ankle or a an ankle injury can cause the os trigonum to be crunched between the ankle and heel bone. As the os trigonum pulls loose, the tissue connecting the bone to the talus can be stretched or torn resulting in swelling/pain/inflammation. 

What are the symptoms of Os Trigonum Syndrome?

Deep, aching pain the back of the ankle especially when pushing off with the big toe. The tendon of the big toe runs right next to the os trigonum, so moving the big toe up and down repetitively can irritate the os trigonum. There is often localized tenderness and swelling at the back of the ankle. 

How to diagnosis Os Trigonum Syndrome?

X-rays are often used to confirm the existence of an Os Trigonum and clinical symptoms of pain with big toe push off with localized tenderness and swelling in the back of the ankle. An MRI is often used to rule out any other issues that could be causing pain. 

How to treat Os Trigonum Syndrome?

Rest, Ice, compression, elevation with immobilization in a long walking boot. NSAIDS or steroids can be taken to help calm in the inflammation. If pain persists than the os trigonum can be removed via open, endoscopic, or arthroscopic approach. 

If you have foot or ankle pain and would like a consultation. Make an appointment at Orange County Podiatry with Dr. Andrew Yang https://ocfootandankleclinic.com/appointments/ or call (949) 651-1202