Knee and patella pain, the possible causes are knee arthritis, meniscus injury, patella trauma and so on. 1. Knee arthritis: knee arthritis refers to the inflammatory reaction of the joints and the surrounding soft tissues, the cause of which is more complex, and may be related to intraosseous hypertension, obesity, metabolic diseases, and joint trauma injury. Due to the inflammatory reaction in the knee joint area, it leads to patellofemoral pain in the knee. 2. Meniscus injury: the occurrence of meniscus injury and a variety of factors are related, such as the angle is not right and the posture is not correct, resulting in meniscus to withstand more than the normal range of capacity, which will occur injury. It can also be due to the knee joint to withstand more than the meniscus can accept the physiological range of friction load, which leads to meniscus injury, causing knee patella pain. 3. Patellar trauma: caused by trauma, such as patellar ligament, soft tissue injury, patellar fracture, etc., may cause local symptoms of severe pain, and can affect the joint flexion and extension activities as well as lower limb weight-bearing walking. Knee and patellofemoral pain may also have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.