Knees become bent, straighten the ringing but not pain, can be handled by the following methods: a, hot compress: if not pain can be hot compress, such as salt bags, microwave, infrared, to play the role of blood circulation and blood stasis, tendon relaxation, sometimes can relieve such ringing; two, acupuncture treatment: if a variety of physical therapy is not effective, acupuncture treatment can be carried out, can loosen the soft tissue, to relieve pain, improve the ringing Third, to clarify the cause, symptomatic treatment: 1, disc meniscus: If the ringing is due to meniscus injury, to carry out the corresponding examination, such as magnetic resonance imaging, to understand whether there is a disc meniscus, there will be such a ringing disc meniscus, but sometimes there is no pain, if the meniscus tear, injury later, it may gradually appear pain, disc meniscus with tearing generally have pain, 2, slippery meniscus. 2, synovial crepitus: when there is a ringing sound without pain, but there are other stumbling phenomena, it may be synovial crepitus, which requires surgical treatment; 3, chondromalacia patella: patellar softening or osteophytes in the process of joint sliding will also appear ringing; 4, the free body of the knee joint appears stuck: the free body of the knee joint appears stuck will appear popping, which is also a more common cause; 5, Osteoarthritis: osteoarthritis causes a lot of osteophytes, bone spur formation, narrowing of the joint space, there will be a ringing in the knee joint; 6, other: rheumatoid arthritis, rheumatoid arthritis, ankylosing spondylitis joint performance, there will also be a problem of straightening with ringing. The cause needs to be clarified and symptomatic treatment is carried out. Therefore, there are many conditions that can cause a ringing sound in the knee joint when it is straightened.