What Causes Popliteal Cyst?

Popliteal cyst is a lesion that occurs in the knee joint. When it occurs, patients may experience symptoms such as joint weakness and pain, which can cause significant discomfort and restrict patients' movements. Popliteal cysts are commonly seen in children and the elderly, and the causes of the disease may vary depending on age. So, what causes popliteal cysts? Below, we will introduce the causes, treatment methods, and clinical manifestations of popliteal cysts.

1. Causes of Popliteal Cyst

If it occurs in adolescents, it is often due to congenital development, especially abnormal development of the tendon synovial membrane inside the congenital popliteal fossa, which can lead to increased abnormal fluid secretion inside the synovial membrane and result in the appearance of popliteal cysts. For popliteal cysts that occur after adulthood, they are mostly caused by chronic strain, especially excessive flexion and extension and weight-bearing activities of the knee joint, which can lead to repeated stimulation and friction of the tendon synovial membrane inside the popliteal fossa, causing increased synovial fluid secretion and gradual formation of cystic masses around the synovial membrane, resulting in popliteal cysts.

2. Treatment of Popliteal Cyst

Popliteal cyst is an abnormal cystic fluid behind the knee joint, that is, enlargement of the bursa and filling with synovial fluid, caused by a problem with the valve mechanism. Generally, it does not cause any symptoms. However, if the swelling compresses nerves or surrounding bones and causes pain or other symptoms, aspiration and puncture can be performed early for treatment. If aspiration is not effective, surgical removal may be considered.

3. Clinical Manifestations of Popliteal Cyst

Popliteal cysts mostly occur in children and the elderly. In children, the cysts are congenital and symmetrical on both sides. In the elderly, they often manifest as knee joint weakness, limpness, and pain at the back of the joint. Large cysts can interfere with the flexion and extension of the knee joint, and may even affect the venous return of the popliteal fossa, resulting in local or below-knee edema. As the cyst grows to a certain size, the flexion and extension of the knee joint may be limited.