Cysts in the popliteal fossa are mainly caused by chronic weight-bearing activities in the knee joint or by direct external forces, resulting in the gradual leakage of joint fluid from the knee joint into the popliteal fossa, which is not absorbed in a timely manner and results in the formation of cysts. When a popliteal cyst develops, the patient will feel pain in the knee joint area, affecting the knee flexion and extension activities, and if there is compression of the surrounding nerves and blood vessels, the patient will also experience numbness and muscle strength loss in the lower limbs. In the treatment, conservative treatment can be taken by applying small needles to pry and loosen the cyst, which can lead to the absorption of the cyst. If the effect is not satisfactory after conservative treatment, surgical treatment can also be considered to remove the cyst by incision.