Posterior Ankle Impingement + Os Trigonum Syndrome

Posterior Ankle Impingement also known as Dancer’s heel can occur in athletes who routinely plantarflex (ankle and toes point downward), such as ballet dancers, jumping athletes, and sports involving kicking. Posterior ankle impingement results from compression of structures posterior to the ankle and subtalar (tibiotalar and talocalcaneal) joints during plantar flexion. The pain is caused by mechanical obstruction due to osteophytes (bone spurs) or pinching of soft tissue structures due to inflammation, scarring or hypermobility.

Posterior Ankle Impingement

Posterior ankle impingement may be caused by bony or soft tissue structures: os trigonum syndrome, flexor hallucis longus tenosynovitis and injury to the posterior ligaments. The os trigonum is the most common cause of symptomatic posterior ankle impingement.

What is the Os Trigonum?

The os trigonum is an extra (accessory) bone that sometimes develops behind the talus bone. It is connected to the talus by a fibrous band. The presence of an os trigonum in one or both feet occurs 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 (7%).

Posterior Ankle Impingement2

What is Os Trigonum Syndrome?

Most people are unaware that they have an os trigonum.

Os trigonum syndrome can be triggered by a single injury, such as an ankle sprain or caused by repetitive downward pointing of the toes, which is common among ballet dancers, soccer players and other athletes.

When pointing the toes downward, the os trigonum can become crunched between the ankle and heel bone, resulting in a “nutcracker injury.” As the os trigonum is moved, the tissue connecting it to the talus is stretched or torn and the area becomes inflamed.


Signs and Symptoms of Os Trigonum Syndrome


After taking a history the foot and ankle are examined, x-rays or other imaging tests (MRI scans) are often required to make the diagnosis.

Treatment: Non-surgical Approaches

Relief of the symptoms is often achieved through treatments that can include a combination of the following:

When is Surgery Needed?

Most patients improve with non-surgical treatment. If the pain persists the 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.

Other types of Posterior Ankle Impingement:

Posteromedial impingement: Following injury to the Posterior Tibiotalar ligament

Posterolateral impingement: Following injury to the Posterior Talofibular Ligament (PTFL)

If you think you might have Posterior Ankle Impingement and would like to discuss your treatment options, complete our Contact Us form and our Medical Secretary will give you a call back.




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