With the improvement of living standards, exercise has gradually become a fashion. However, the number of joint injuries caused by inappropriate sports is also increasing. The knee joint is the most complex joint in the human body, and it is also the most vulnerable to injury during exercise. People often seek medical attention for knee pain, and meniscus injuries account for a high percentage of knee injuries. What is the meniscus? It is a pair of wedge-shaped, half-moon shaped cartilage structures located between the femur and tibia in the knee joint. When a person is active, it acts as a shock absorber, relieves pressure, and protects the cartilage in the knee joint. The meniscus ruptures when subjected to excessive pressure and shear during strenuous activity. Or due to ageing, the meniscus itself may change in structure, and a small external force such as a sprain or even a squat may cause damage to the meniscus. A series of symptoms such as knee pain, swelling, impaired mobility and muscle atrophy can occur. Most meniscus injuries are treated with surgery. Due to the special structural characteristics of the meniscus, only a part of the meniscus can be repaired after the injury, and most of it has to be removed because it cannot be repaired. After the meniscus is removed and after a period of rehabilitation, most people’s symptoms from the original injury will disappear. “Born to be useful”, man is like a precision machine in the process of evolution, and all organs have irreplaceable roles to play. When the meniscus is removed its role in protecting the knee joint is gone, and subsequently osteoarthritis of the knee joint occurs earlier. And there are still some people who always feel discomfort and recurring pain in the affected knee even after meniscectomy. In the past, there would have been essentially nothing that could have been done about the complications after meniscectomy. During follow-up after meniscectomy, patients often ask: “Can’t we get another meniscus if there’s no more meniscus?” This is certainly possible. But because of technology and other reasons in the past this was not possible to solve. Science is endless, and in recent years it has been made possible with advances in medical technology. The development of science and technology has brought the gospel of human health, and previously untreatable and difficult diseases have now been solved. Arthroscopic observation of meniscus defects now