Swollen and painful joints: 1. May be caused by autoimmune diseases, such as rheumatoid arthritis, gouty arthritis and rheumatoid arthritis, which can cause significant joint effusion and synovial edema after joint erosion, resulting in swelling and pain in the joint. 2. 3. abnormal friction of the internal degenerative cartilage, resulting in obvious swelling and pain in the joint. 4. may also be due to trauma, especially after trauma, causing damage to the joint capsule, internal cartilage, synovium or surrounding ligaments, resulting in obvious swelling and pain in the joint, and affecting joint flexion, extension and weight-bearing activities.