While the majority of fistulas in ano result from infection of the anal crypts, complex, recurrent, and/or nonhealing fistulas should always raise the suspicion of a chronic underlying condition. In this paper, we present a 30-year-old male patient with a diagnosis of a complex suprasphincteric fistula caused by a surgical thread left behind after an orthopedic hip operation performed sixteen years ago. Partial fistulectomy, extraction of the foreign material, and debridement procedures were performed. Few cases of such complex fistulas in ano due to foreign materials have been described in the literature. After careful history-taking, meticulous physical examination under general anesthesia should be done in order to deal with this rare type of fistula.