The os trigonum is a small additional bone that is located at the backside of the ankle at the talus bone. According to estimations, 3-15 % of adults have an os trigonum that may cause several symptoms.
Patients suffering from os trigonum syndrome can feel pain at the backside of the ankle often accompanied by swellings. Generally, it is a permanent pain that worsens significantly when straining the ankle. Besides these symptoms, os trigonum syndrome may also cause stiffness and weakness of the ankle.
Symptoms of os trigonum syndrome in short:
The existence of the os trigonum is congenital, but does not necessarily lead to the os trigonum syndrome. The syndrome may emerge if the foot is repeatedly strained, for example, due point positions during toe-dance in ballet, supporting or pushing off the feet while climbing or kicking the ball using the arch of the foot during soccer, football or rugby. The os trigonum syndrome can also become a chronic disease.
In case of an assumed os trigonum syndrome, a comprehensive orthopedic examination is carried out often accompanied by imaging procedures X-raying or MRI. The existence of the os trigonum can be proven by X-raying.
The best method to differentiate between different injuries is MRI. MRI enables us to visualize very different structures during one examination like muscles, ligaments, tendons, cartilage and bones. If it is necessary, we do also apply a well-tolerated contrast agent to improve the visibility of certain structures.
The os trigonum syndrome can be treated conservatively or surgically. Conservative therapy encompasses injections of painkilling or corticoid drugs, orally taken antirheumatic drugs, physiotherapy and special footgear, if necessary. Persisting symptoms may indicate surgery.