Sore and swollen leg joints can be caused by physiological factors such as prolonged standing or squatting, as well as pathological factors such as joint effusion, periarticular synovitis and degenerative changes in the joints. 1. Physiological factors: prolonged standing or squatting will increase the load on the joints, make the joints stiff, and affect the local blood circulation in the joints, which will cause soreness and distension in the leg joints. 2. Pathological factors: After a large amount of fluid accumulates around the leg joints, the muscles and blood vessels around the joints will be affected, resulting in soreness and swelling. Inflammation of synovial membrane around the joints will cause local soft tissue edema, poor blood circulation and soreness. When degenerative joints occur, it will compress the surrounding soft tissues, causing muscle damage and soreness and pain. Therefore, when the leg joints have soreness and pain, we should go to the orthopedic department of the hospital in time, in order to clarify the cause of the disease and actively cooperate with the doctor for treatment.