Swollen and painful knees that cannot be bent need to be treated according to the cause of the disease. Common causes include knee muscle strain, trauma, synovitis and so on, and the treatment includes rest, physical therapy, medication and so on. 1. Knee joint muscle strain: localized soreness and swelling, uncomfortable feeling, and in severe cases, pain, need to rest, local hot compresses or physical therapy. 2. Trauma: trauma can lead to soft tissue damage caused by pain, there may also be joint effusion resulting in knee swelling, to brake and rest, non-steroidal anti-inflammatory drugs such as aspirin, ibuprofen and so on. 3. Synovitis: the main symptoms of joint swelling, pain, limited mobility. To rest more, can choose non-steroidal anti-inflammatory analgesic drugs such as ibuprofen, celecoxib and so on. There may be other causes of knee swelling and pain, such as arthritis, etc. If the symptoms do not improve after rest, you need to go to the hospital in time to find out the cause of the disease, and give the appropriate treatment and treatment. The above medications should be used under medical supervision.