A 4-month old rostro-humeral ligament injury can still be treated. Depending on the severity of the rostro-humeral ligament injury and the clinical manifestations, appropriate treatment measures such as medication and surgery should be taken. If the rostro-humeral ligament is simply injured with pain, localized swelling, positive tenderness and some degree of restriction of shoulder joint movement, local plaster cast or brace immobilization can be chosen after 4 months. Combined with the use of pain medication such as ibuprofen for treatment. If the rostro-humeral ligament is completely ruptured, it will lead to shoulder instability, and shoulder movement will be limited. 4 months later, minimally invasive surgery for rostro-humeral ligament repair with shoulder arthroscopy can be considered, and braking and immobilization of the shoulder should also be done after the surgery. Patients can gradually carry out functional training of the shoulder joint under the guidance of the doctor, so that the affected limb can get normal loading and flexion/extension movements.