If the injury to the medial posterior horn of the meniscus is only a contusion, edema, or small partial tear, and its tear length is not large, it can heal spontaneously. However, self-healing is only functional; for example, after a first-degree injury, the edema can resorb and the contusion will gradually resolve. After a small tear, the meniscus is usually not repaired because it has no repair function, but it does not affect walking or bending. After a meniscus injury, it can heal on its own with certain conservative treatments such as braking, baking, heat application, iontophoresis, and restorative exercises, and without pain when walking. If it is a degree II injury or a degree III injury, and it does not improve after treatment, and MRI examination reveals that the posterior horn of the meniscus is completely torn, or the length of the meniscus tear is long and the middle of the meniscus is split, then arthroscopic surgery should be considered for treatment.