As arthroscopic surgery continues to be performed, the concept of meniscal injury is becoming more accepted, but there is a misconception about surgical treatment. Nowadays, when meniscus injuries are mentioned, people start to worry about the effectiveness of surgery. Not all meniscus injuries require surgery! Meniscus injury is a general concept. First, it is important to clarify if it is a meniscus injury, and second, what kind of injury it is. According to the location of meniscus injury, the degree of injury and different pathological characteristics, meniscus injury is divided into: meniscus tear, meniscus degeneration (peri-meniscus), discoid meniscus injury, meniscus overactivity and meniscus cyst. The treatment principles for each injury type are not consistent and not all problems can be solved by surgical treatment alone. The different treatment principles are explained one by one in future articles. There is also a serious misconception that friends or family members of patients now often come with just MRI films to inquire about the need for surgical treatment, or even worse, just MRI report cards without even a film. Magnetic resonance imaging (MRI) is a reliable imaging technique for diagnosing meniscal injuries of the knee, with the advantages of high accuracy, low false-positive and false-negative rates, and non-invasiveness. Under normal conditions, all sequences of MRI are low signal because there are only trace amounts of free protons in the meniscus. When the meniscus is torn, MRI can show abnormal signal within the meniscus, abnormal size and abnormal morphology of the meniscus to determine meniscal injury. However, ancillary tests are not a substitute for a physical examination of your knee, and the most important diagnostic process during your visit should be a combination of history taking, physical examination, and viewing of imaging data. Only if the degree of your pain, the location of the pain or interlocking, and the positive signs found by your doctor on examination and the pain on examination are consistent with the site of meniscal damage on your MRI will truly constitute a sufficient reason for arthroscopic surgical treatment.