Ultrasonography-Guided Flexor Hallucis Longus Tenotomy for Checkrein Deformity of the Hallux

The checkrein deformity of the flexor hallucis longus (FHL)-resulting from tibial, fibular, and/or talar fractures, removal of a fibular graft, and so on-increases with dorsiflexion of the ankle, but plantar flexion of the ankle can partially correct the deformity. In this article, ultrasonography-guided FHL tenotomy for checkrein deformity of the hallux is described. The operative procedure is performed in the supine position, and the ultrasonic probe is placed on the posterior side of the medial malleolus. Then, 1% lidocaine is injected to separate the neurovascular bundle from the FHL under ultrasonography so that the FHL tendon can be picked up safely. The FHL is subsequently cut under direct vision. Weight-bearing and range of motion are allowed as tolerated, according to pain, starting 1 day after surgery. Ultrasonography-guided FHL tenotomy for checkrein deformity of the hallux requires some ultrasound training, but it is a very promising procedure because it is safe and less invasive than open procedures.