The pain on the inner side of the knee can not be bent may be related to rheumatoid arthritis, muscle ligament strain, osteoarthritis, meniscus injury, etc., the cause of the disease should be clarified, and the treatment should be directed to the cause of the disease. 1. Rheumatoid arthritis: knee pain, activity limitation, mostly accompanied by local redness, swelling, heat, pain and so on. Anti-rheumatoid drugs can be given for treatment, such as methotrexate, leflunomide and so on. 2. Muscle ligament strain: the muscle ligaments around the knee joint are easily damaged in ordinary sports, local pain and activity limitation, etc. It should be properly braked and rested, and local physical therapy can be given to relieve the pain. 3. Osteoarthritis: it occurs in knee joint, hip joint, wrist joint and spine, often accompanied by pain, stiffness, swelling, activity limitation and joint deformity. It should reduce the weight of joints, take sufficient rest, reduce the weight of obese people, and also give hot compresses, physical therapy, medication (such as celecoxib, glucosamine, etc.), and if necessary, surgery can be carried out. 4. Meniscus injury: manifested as knee pain, swelling, dysfunction. After meniscus injury, generally choose conservative treatment, should immediately stop the activity, the knee joint bandage immobilization, and actively carry out quadriceps exercise to avoid muscle atrophy. Non-steroidal anti-inflammatory drugs can be given to anti-inflammatory pain relief, such as diclofenac sodium, celecoxib and so on. If the injury is serious, surgery can be performed. Inside knee pain can not bend there may be other reasons, it is recommended that timely hospital visits to identify the causes, and then give targeted treatment or treatment, the above medication should be used under the guidance of a doctor, to avoid self-medication.