This report presents an athletic patient with swelling and progressive pain on the posteromedial side of his right ankle on weight bearing. MRI demonstrated tenosynovitis and suspicion of a length rupture. On posterior tibial tendoscopy, there was no rupture, but medial from the tendon a tissue cord came into view, causing impingement on the tendon at the level of maximum pain. The cord was released and 2 weeks and 1 year after the procedure the patient reported no complaints.