Posterior debridement for ankle impingement. A, Patient positioning. B, Posterolateral portal. C, Insertion of hemostat aimed along line directed to first web space. D, Insertion of arthroscope through posteromedial portal. E, Insertion of arthroscopic shaver. F, Identification of flexor hallucis longus. G, Exposure of os trigonum. SEE TECHNIQUE 50.2.