A novel technique of arthroscopic excision of a symptomatic os trigonum.

We describe a new arthroscopic excision technique for a symptomatic os trigonum. With the patient lying in a prone position, a posterolateral portal just lateral to the Achilles tendon, at the 5-mm level proximal to the tip of the fibula, is used for the arthroscope and an accessory posterolateral portal just posterior to the peroneal tendon at the same level is used for instruments. The synovial tissues are then debrided with a power shaver through the accessory posterolateral portal for better visualization. An elevator is used to release the fibrous tissue between the os trigonum and the talus. The os trigonum is completely excised with a grasper to visualize the flexor hallucis longus tendon. Radiographic control is helpful to check the position of the arthroscope if it happens to be inserted into the ankle joint as a result of the reduced subtalar joint space. Postoperatively, no immobilization is necessary, and full weight-bearing is allowed as tolerated. Three of us have performed 11 procedures with excellent results and no cases of complications. This arthroscopic excision technique for the symptomatic os trigonum is a safe and effective procedure.