Ankle cysts are commonly caused by the following reasons: a. Degenerative changes in the tendon sheath of the ankle tendon, cysts can affect the tendon activity, and patients can have local pain, and the cysts can be confirmed as tendon sheath cysts through ultrasound examination. Second, degenerative synovitis of the ankle joint can form a large amount of joint fluid, and too much joint fluid accumulation can form periarticular cysts. Surgery is the preferred treatment for cysts in the ankle joint. Surgery can completely remove the cyst and prevent recurrence. If the cyst is connected to the joint cavity, it is also necessary to consider arthroscopic examination of the foot and ankle and surgery to remove the lesion in the foot and ankle joint in order to finally solve the cyst in the foot and ankle joint cavity.