The diagnosis of the os trigonum syndrome with a fluoroscopically controlled injection of local anesthetic.

PURPOSE: To report the results of excision of the os trigonum using a fluoroscopically controlled injection of local anesthetic to diagnose the os trigonum syndrome. DESIGN AND PATIENTS: Os trigonum syndrome is a recognized cause of pain in the posterior aspect of the foot and ankle. The symptoms and physical findings, however, are often nonspecific and difficult to differentiate from other causes of posterior ankle pain. We report four patients with persistent posterolateral ankle pain despite prolonged nonoperative treatment. An os trigonal syndrome was diagnosed by a positive response to a fluoroscopically guided local anesthetic injection in the region of synchondrosis between the os trigonum and the posterior talus.
RESULTS: All four patients underwent excision of the os trigonum with complete resolution of symptoms and return to full activity.
CONCLUSIONS: Fluoroscopically controlled injection can help confirm the suspected diagnosis of an os trigonum syndrome and may have positive predictive value regarding the outcome of excisional surgery.