Knee pain can be caused by a variety of factors. 1. Trauma to the knee joint may result in damage to the meniscus, cruciate ligaments, collateral ligaments, and bony structures of the knee joint, resulting in swelling and inflammatory edema, which can cause painful symptoms due to peripheral nerve irritation. 2. 3. Synovitis of the knee joint, when the synovial membrane is affected by cold or external irritation or overexertion, local inflammatory edema may form, which may also cause significant pain. 4. Arthritis, such as high uric acid purine metabolism abnormalities, which will lead to the formation of uric acid deposits or gout stones in the knee joint, will also form a sense of knee pain.