Hidden pain one year after knee injury may be meniscus injury, cartilage injury, ligament injury, synovitis and lumbar spine disease, can be treated with oral medication, and in severe cases can be treated with surgery. 1. Meniscus injury: Hidden pain one year after knee injury generally indicates that there is knee injury, common meniscus injury. Mild meniscus injuries can be treated conservatively. Severe meniscus injuries require minimally invasive arthroscopic surgery for suturing or molding. 2. Cartilage injury: knee injury can cause femur or tibia platform cartilage damage, cartilage damage is difficult to heal, can appear a year after the knee injury hidden pain. You need to take some oral nutritional cartilage drugs such as glucosamine capsules to improve the damaged cartilage tissue. In serious cases, surgical treatment such as cartilage transplantation may be needed. 3. Ligament injuries: Cruciate ligament and medial collateral ligament injuries can remain painful for up to a year after the knee injury. Treatment requires oral non-steroidal anti-inflammatory drugs such as ibuprofen. 4. Synovitis: knee injuries can cause chronic inflammation of the synovium, which can persist for a long time, resulting in clinical symptoms of vague pain one year after the knee injury. It can be treated with intra-articular injection of drugs such as lidocaine and prednisolone. 5. Lumbar spine diseases: Lumbar spine diseases such as lumbar disc herniation and lumbar spine slippage can cause vague pain in the knee one year after the knee injury. You need to take anti-inflammatory painkillers such as ibuprofen orally. In severe cases, surgical repositioning and internal fixation are needed. It is recommended to go to the hospital as soon as possible for formal treatment of hidden pain one year after knee injury.