Chronic ankle instability is defined as recurrent ankle sprains over at least one year resulting from trauma. It is usually caused by incomplete healing of injured lateral ankle ligaments from previous sprains. Physical exam involves tests like the anterior drawer test and talar tilt test to assess instability. Non-surgical treatment focuses on strengthening and proprioception training. Surgery is considered if instability symptoms persist after 3-6 months and involve either anatomic repair or reconstruction of the lateral ligaments, or non-anatomic stabilization procedures. Post-operative rehabilitation focuses on range of motion exercises and gradual return to weight bearing and sports.