Pain inside the knee of the right leg, commonly due to age-related arthritis, right knee synovitis and other causes, as follows: First, age-related osteoarthritis: mainly related to excessive weight bearing, long-term wear and tear, the patient will show symptoms of right leg joint pain, accompanied by limited knee joint activities, serious cases will have joint enlargement, hyperplasia, deformation, the patient can not normal weight-bearing walking, and even limp, line X-ray can confirm The diagnosis can be confirmed by X-ray. Second, right knee synovitis: Young patients with cold or sports injuries to the knee joint can cause acute synovitis of the knee joint, which can manifest as pain, swelling, joint effusion in the right knee joint, as well as a marked increase in skin temperature and limitation of joint movement, and the diagnosis can be confirmed by MRI. Pain in the right knee requires early treatment with knee braking to provide satisfactory relief of symptoms.