There are several possible causes of knee pain: first, osteoarthritis, osteoarthritis in the early stage can appear in the knee joint mild pain, which can be accompanied by knee joint swelling and knee joint movement restrictions, then the knee joint X-ray, nuclear magnetic examination for early diagnosis and treatment; second, patellofemoral arthritis of the knee joint, patellofemoral arthritis of the knee joint can appear in the knee joint Patellofemoral arthritis can lead to chronic aseptic inflammation of the patellofemoral joint, resulting in cartilage damage, resulting in knee joint pain. Blood tests, x-rays and CT examinations of the knee joint should be performed for early diagnosis and treatment.