Knee pain can be related to osteoarthritis, chondromalacia patella, knee tuberculosis, meniscus injury of the knee, rheumatoid arthritis and other causes. 1. Osteoarthritis: it may be related to heredity, obesity, trauma and other reasons. It can cause knee joint pain, which is obvious during excessive activities and can be relieved after rest, as well as morning stiffness, muscle atrophy, limited joint movement and deformity. 2. Chondromalacia patella: It can be related to patellar development disorder, knee valgus, long-term exertion of the knee joint and other reasons. It can cause knee pain, mainly infrapatellar or anterior knee pain, which can lead to squatting, difficulty in going up and down steps, sudden fall and so on. 3. Knee tuberculosis: It is caused by Mycobacterium tuberculosis infection. It can cause knee joint pain, swelling, limping, deformity, as well as accompanied by low fever, fatigue, loss of appetite, emaciation and other symptoms. 4. Knee meniscus injury: grinding force is the main cause of meniscus injury. It can cause knee joint pain, as well as symptoms such as limited movement, swelling and muscle atrophy. 5. Rheumatoid arthritis: it can be related to heredity, bacterial infection and other factors. Rheumatoid arthritis can cause knee pain, accompanied by finger and metacarpophalangeal joint pain, swelling, morning stiffness, fatigue and other symptoms. Knee pain is also related to trauma and other causes, you need to go to the hospital in time, clear the cause of the disease and follow the medical advice treatment, avoid self-medication.