Ankle joint pain at bedtime is commonly caused by cold at night and arthritis, the details are as follows: 1. Cold at night: The first ankle joint gets cold during sleep at night, the patient will have acute synovitis of the ankle joint, resulting in pain and swelling of the ankle joint and limited joint movement in the morning. 2. Sudden onset causes severe pain in the ankle joint when the patient wakes up in the morning, accompanied by joint stiffness and limited joint movement, and it usually takes about an hour to restore the range of motion of the ankle joint, and the rheumatic series examination is usually positive. Patients with morning pain in the ankle joint should be diagnosed and treated promptly, and the symptoms of ankle joint pain should be strictly controlled, and attention should be paid to protecting the ankle joint in general to avoid the occurrence of symptoms.