Pain inside the right knee, commonly associated with senile arthritis, synovitis of the right knee joint and other causes, as follows: First, senile osteoarthritis: mainly associated with excessive weight-bearing, long-term wear and tear, the patient will be manifested in the right leg joint pain symptoms, accompanied by limited knee joint activity, the serious will have joint expansion, hyperplasia, deformity, the patient can not walk with normal weight-bearing, and even claudication, the line of X-rays can be confirmed! Diagnosis. Second, the right knee synovitis: young patients with knee cold or sports injuries, will cause acute synovitis of the knee joint, will be manifested as the right leg knee joint pain, swelling, joint effusion, as well as a significant increase in skin temperature, joint activity is limited, through the MRI can be diagnosed. Early treatment of pain in the right knee joint, together with knee braking, is required to achieve satisfactory symptomatic relief.