The knee joint is the most complex joint in the human body, with a relatively large joint surface, more ligaments, and with a large load and superficiality as its anatomical characteristics. Knee pain has the following causes: 1, pediatric knee pain: may be growing pain, another cause is calf tibial tuberosity epiphysitis can also cause knee pain; 2, patellar chondromalacia: can occur in young adults or older; 3, knee degenerative arthritis: mainly occurs in middle-aged and older and more female patients; 4, knee meniscal injury: can cause knee pain; 5, knee joint Septic infection: can also cause knee pain; 6. Knee synovitis, bursitis, etc.: can cause knee pain; 7. Rheumatoid arthritis: involves the knee joint and can also cause knee pain. Knee pain can be caused by one disease or multiple diseases can cause knee pain.