Os-Trigonum/Posterior Ankle Impingement Syndrome
What is it: Posterior ankle impingement syndrome is posterior ankle pain that occurs in forced or repetitive plantar flexion. An os-trigonum is a small accessory bone that does not fuse with the rest of the talus. It is located in the posterior part of the ankle and repetitive plantar flexion in the presence of this accessory bone is the most common cause of this syndrome.
How does it present: The patient may present with acute onset of posterior heel pain after a forced plantarflexion or may have repetitive plantarflextion injury, such as with dancers on point or ice skaters.
Common exam findings: Exam may reveal tenderness or swelling over the area of the posterior heel.
Tests and treatment: Ankle x-rays may reveal the os-trigonum. Treatment is generally conservative, but surgical excision of the os trigonum may be necessary.