The common causes of foot joint effusion are as follows: 1. Due to acute injury, acute injury can lead to local vascular rupture and bleeding, resulting in corresponding hemorrhagic effusion. 2. The presence of arthritis in the foot joints, such as rheumatoid arthritis, rheumatoid arthritis, synovitis, etc., are due to immune factors that lead to joint inflammation and inflammatory effusion. 4. Certain diseases, such as poor blood circulation in the lower extremities, lead to blood pooling in the veins of the feet, and when the venous pressure is high, it also leads to an increase in blood and intertissue fluid, which can lead to effusion in the foot joints, and at the same time The foot will also be accompanied by significant swelling.