(v) Chronic ankle instability

Injuries to the ligaments of the ankle are common, especially in athletes. Symptomatic ankle instability develops in as many as 10–40% following an acute injury. The causes of symptoms are multifactorial, encompassing pre-existing patient factors predisposing to instability, functional instability and mechanical instability. Chronic ankle instability occurs when patients suffer recurrent episodes of ankle sprains and the majority can be successfully treated with a functional rehabilitation programme. Those that fail require consideration of surgical intervention. A full history, clinical examination, radiological investigation and an understanding of the pathomechanics involved are vital to ensure that the most appropriate surgical strategy is adopted. Pain and swelling are commonly associated symptoms and may be more disabling than the episodes of instability. Concurrent intra and extra-articular pathologies must be addressed to achieve a successful functional outcome. Surgical options include arthroscopy, ligament reconstruction techniques, hindfoot alignment procedures and gastrocnemius release. This article focuses on the anatomy, pathomechanics and treatment of chronic lateral ankle instability. Medial, syndesmotic and subtalar instability are also discussed.