Hi. Cause of Synovitis of knee has to be determined. It can be infective or inflammatory. The fluid can aspirated and send for examination to find out the cause and accordingly medication can be prescribed. If the pain and swelling is persistent for more than 3 months then consider getting MRI knee to find the cause.
Next Steps
Ice pack application and consider seeing a specialist orthopaedic or knee surgeon
Health Tips
Regards
Dr Sachin Jain
Arthroscopic surgeon and sports medicine expert, Jaipur