Pediatric synovitis may be related to trauma, viral infection and other factors. 1. Trauma: children with increased activity and falls, such as running, swimming, sprains, etc., may lead to increased friction frequency or injury to the joints, resulting in synovial swelling, oozing and so on, leading to synovitis. 2. Viral infections: If a child has recently had a cold, it may also lead to the above symptoms, accompanied by a bumpy walk, which will return to normal with proper rest. Pediatric synovitis may also have other causes, it is recommended to go to the hospital in time for relevant examinations, to clarify the cause of the disease and then actively treat the symptoms.