The causes of right knee pain on the outside of the knee may be chronic strain, knee trauma, ligament inflammation, osteoarthritis and so on. 1. Chronic strain: If the patient is engaged in physical labor or excessive exercise for a long time, frequent use of the knee joint may cause chronic strain of the knee joint, and the local soft tissues, nerves, bones and other tissues may be subjected to a certain degree of wear and tear, causing pain. 2. Knee trauma: due to strenuous exercise or trauma can lead to meniscus injury or lateral collateral ligament injury, etc., which will cause pain on the outside of the knee, accompanied by symptoms such as swelling of the knee joint and limited joint movement. 3. Ligament inflammation: it is a kind of sterile inflammation, related to sports injury or chronic strain, which can cause inflammation of the lateral collateral ligament of the knee joint, thus leading to pain in the lateral part of the knee joint. 4. Osteoarthritis: degenerative lesions of the knee joint can cause osteoarthritis, resulting in pain, stiffness, swelling and other symptoms of the knee. Right knee pain can also be seen in other causes, it is recommended that patients seek medical treatment in time, under the diagnosis and guidance of a professional doctor for treatment.