Knee pain at the age of 30 may be related to trauma, septic arthritis, tuberculous arthritis and other lesions. 1. Trauma: when the knee is hit or sprained, it can lead to ligament injury, meniscus injury, patella fracture and other knee injuries, causing knee pain, accompanied by knee swelling, bruising, limited movement and other symptoms. 2. Septic arthritis: due to bacterial infection such as Staphylococcus aureus, it can cause septic inflammation of the knee joint, resulting in symptoms such as swelling, fever and pain in the knee joint, which also affects the mobility of the joint. 3. Tuberculous arthritis: patients with a history of tuberculosis can be infected by tuberculosis bacilli in the knee joint, causing knee joint pain, swelling, limited mobility and other symptoms, which can also be accompanied by systemic symptoms such as low-grade fever, night sweats and so on. 30-year-old knee pain may also be caused by other reasons, it is recommended that patients go to the hospital in time to improve the relevant examination for targeted treatment.