Pain inside the knee bone may be caused by degenerative lesions of the knee joint, trauma, autoimmune diseases and so on. 1. Degenerative disease of knee joint: most of the pain inside the knee joint bone is secondary to degenerative disease of knee joint, which will lead to the emergence of bone cumbersome and synovial growth in the joint, resulting in the narrowing of the joint space, cartilage damage, etc., which will affect the normal activities of the joint, and the symptoms mentioned above will appear. 2. Trauma: Trauma to the knee joint will directly affect the knee, such as tibial plateau fracture, intercondylar ridge fracture, etc. These factors will lead to abnormalities in the articular surface of the knee joint, resulting in collision between the bones and interlocking of the joints, which will lead to pain symptoms. 3. Autoimmune disease: When autoimmune disease is combined with autoimmune disease, it will lead to the immune reaction of autoantibodies and antigens in the knee joint, resulting in the deposition or aggregation of immune complexes and inflammatory factors, which may also lead to pain inside the knee bone. The cause of knee pain cannot be accurately determined by the symptoms alone, and it is necessary to combine the characteristics of the medical history and other test results to make an accurate judgment, and it is recommended to clarify the cause of the disease under the guidance of a doctor.