Acute ankle instability is a frequent injury in young and active folks and can unfortunately quite often (in 20–40 %) proceed to chronic ankle instability. Fifty-five percent of the injuries leading to ankle instability are due to sporting accidents. Symptomatic chronic ankle instability is considered as a pre-osteoarthritic condition and long-term results without adequate therapy are poor. There are different types of chronic ankle instability and consequently functional ankle instabilities are mainly treated conservatively while mechanical ankle instabilities often need a surgical treatment after failed conservative treatment. Ankle arthroscopy seems to be are valuable tool for ankle instability diagnostics and can be used for direct treatment of adjunctant injuries as well. Anatomical ligament reconstruction has been proven to be superior to non-anatomical surgical techniques in clinical investigations. Relevant concomitant injuries (hindfoot malalignment, tendon problems, osteochondral lesions, etc.) should be treated simultaneously to ligament surgery.