Osteochondritis dissecans may be caused by stress injury, bacterial infection, tumor tissue invasion and so on. 1. Stress injury: due to less exercise, unreasonable exercise method and excessive exercise, the periosteum is repeatedly pulled, causing damage to the periosteum and inflammatory changes leading to periostitis. 2. Bacterial infection: As the periosteum is traumatized, it is easy for bacteria to invade and cause infection, which may lead to periostitis when the condition further develops. 3. Tumor tissue invasion: if the patient himself suffers from tumor disease, with the development of the disease, the tumor may invade the periosteum, thus inducing periostitis. After the occurrence of periostitis, patients should go to the hospital for examination in time, actively search for the cause of the disease, and take corresponding treatment measures under the guidance of doctors.