The causes of inexplicable swelling and pain in the ankle may include: 1. injury to the ankle joint and its surrounding muscles or ligaments, which can often be relieved by rest and local analgesic creams. 2. hyperuricemia and gouty arthritis caused by gout, resulting in local swelling and pain, usually due to diet, which can be clarified by local X-rays and blood uric acid measurements. 3. thrombosis or embolism of blood vessels in the lower limbs, resulting in local swelling and pain, which can be clearly diagnosed by vascular ultrasound. 4. This can be clearly diagnosed by vascular ultrasound. 4. Edema of the ankle joint in patients with nephritis and nephritis, resulting in swelling and pain due to obvious compression of local tissues.