Os trigonum, case report

Abstract

A 21-year-old female patient with a history of right calcaneal pain since childhood presented with a grade II right ankle sprain following a fall down the stairs. Physical examination revealed edema, ecchymosis, and positive instability tests. Radiographic findings showed the presence of an os trigonum, an anatomical variant that predisposes to os trigonum syndrome with posterior ankle pain, particularly during activities involving repetitive plantar flexion. The patient was treated with immobilization and anti-inflammatory medications, with no evidence of fracture. This case highlights the importance of considering anatomical variants as a cause of ankle pain, especially in patients with a history of recurrent sprains.