Persistently Painful Sprained Ankle.

Chronic discomfort sufficient to limit activity may affect 20% to 40% of patients after an ankle sprain. These patients complain of vague and diffuse pain, most often localized to the lateral and/or anterolateral aspect of the ankle. They may also complain of a giving-way sensation, swelling, stiffness, and locking and crepitation. Examination may show tenderness, swelling, and reduced range of motion, especially in dorsiflexion. Ankle instability is sometimes demonstrable. Severe cases exhibit discoloration, glossy skin, and temperature changes suggestive of reflex sympathetic dystrophy. Incomplete rehabilitation is the most common cause of chronic pain. Other common problems are intra-articular lesions (e.g., osteochondral and meniscoid lesions), chronic instability, undetected syndesmotic or deltoid sprains, chronic tendon degeneration, stress fractures, and, in rare cases, congenital lesions and tumors. Reflex sympathetic dystrophy occurs occasionally, even after minor trauma. With correct diagnosis and appropriate treatment, it is often possible to restore acceptable ankle function