Ankle sprain is a very common injury, most people can get better after 2-6 weeks of treatment such as ice, elevation, braking and compression bandage, but in the outpatient clinic, we often encounter many cases that have not improved for more than 3 months, which accounts for about 20% of the cases. We call this “chronic lateral ankle instability”. What causes ankle sprains to stay bad? What causes ankle sprains to become chronic? 1, the injury ligament damage is serious, often at the time of injury can be heard in the ankle joint, anterolateral swelling is very obvious, which suggests that the ankle ligament has the possibility of rupture. General rupture of the ligament for the anterior talofibular ligament (red circle position in the figure). 2. In the case of ligament rupture, without regular treatment (e.g. cast or brace immobilization), after a period of time, although you can walk, but the ligament has not healed, so there are still uncomfortable symptoms, or frequent sprains of the foot phenomenon. When should I seek medical help? When one of the following situations occurs, you need to go to the hospital to seek medical help: ankle sprain for more than 3 months and there is still pain, swelling and other uncomfortable symptoms, or walking on a flat road will often appear twisted foot; long-distance walking after the ankle pain, swelling symptoms; in the process of walking, there is “flash” or “flickering” or “weak legs” when walking; need to be careful when walking down stairs, fear of twisting the ankle, or feel that it is difficult to control the ankle; have difficulty changing direction in sports; women are unable to wear high-heeled shoes. What will my doctor do? When a patient with a chronic ankle sprain goes to the hospital and sees a specialist, the doctor will ask questions to find out about the injury and current symptoms, and the doctor will conduct a physical examination (critical) to determine if the ligaments are torn. If the doctor determines that the ligament has a problem, the doctor will request a further ultrasound examination (economical, quick, but not sensitive to the judgment of combined injuries) or an MRI (more expensive, need to wait, but sensitive to the detection of combined injuries, which is conducive to the doctor’s judgment and to give a treatment plan). What will happen if I don’t get treatment? Patients in the clinic often ask what will happen if they are not treated? After chronic lateral ankle instability occurs, because the ankle joint needs to bear several times the force of the body in daily activities, due to the instability of the ankle joint is prone to impingement, and traumatic inflammation of the ankle joint occurs over time, and the typical symptom is the pain in the area of the ankle joint, which usually occurs within six months or so, and if the symptoms persist, it is necessary to eventually undergo fusion of the ankle joint or ankle joint replacement. However, if chronic lateral ankle instability is detected and treated early, the prognosis is generally good.