The knee joint rattles during deep squatting, the following common causes: First, the patient has a meniscal injury rupture, meniscal injury is a common joint sports injury in young adults, the ruptured meniscus will deform when the joint flexes and squeezes, jamming, resulting in pain, jamming and emitting a popping sound, at this time, you should promptly seek medical advice and do an MRI to clarify the diagnosis. Second, poor patellofemoral joint alignment, patellar subluxation or dislocation may occur during deep squatting, and emit a loud sound. In this case, the patient should be seen in joint surgery or sports medicine department in time. Second, the patient suffers from arthritis, mainly degenerative arthritis, in the process of squatting, the joint surface appears serious friction, and the joint surface is rough, so it will also produce joint ringing and joint pain. If the joint rattles when squatting, you should avoid squatting for a short period of time, and you should check the condition of the knee cartilage. If the posture is incorrect, the squatting position needs to be corrected. If it is osteoarthritis, the cartilage damage should be actively treated.