Knee arthroscopy is a minimally invasive procedure that orthopedic surgeons can use to see and even treat most patients with knee problems. The orthopedic surgeon makes only tiny incisions in the knee joint and inserts a 4 mm lens and fiber optics inside the knee joint. The images acquired by the lens are connected to a screen for diagnostic treatment. Many people are now familiar with this technology and the use of knee arthroscopy has become quite common. The most significant advantage of arthroscopy is the ability to view multiple angles within the joint. In the past, to view these areas would have required an incision in the joint and flipping the patella out of alignment. This procedure added additional trauma and risked damaging the joint. In contrast, arthroscopy causes minimal damage to the surrounding soft tissues and can provide information that many other methods cannot. This includes information obtained by probing the soft tissues, and the soft tissue information provided by MRI provides a good assessment of the soft tissue structure, but does not assess the tactile information that cannot be evaluated underneath. In terms of treatment, arthroscopy avoids the need to make larger incisions, and ACL reconstruction and repair of torn menisci are the most routine arthroscopic procedures. The different structures within the knee joint have different functions. The ACL helps stabilize and support the knee joint, there are two menisci within the joint that absorb shock and distribute the stresses through the joint, and the articular cartilage’s cover the surface of the bone ends to provide a smooth surface during movement. Injuries to the ACL and meniscus are very common, especially during sports. This means that a person with an ACL injury is also at high risk of injury to the meniscus. In recent years, the gender bias of ACL injuries in young female athletes has been elucidated, with women being 2-6 times more likely to injure the ACL than men. Very few ACL and meniscus injuries can be treated non-surgically with rest, physical therapy, and changes in exercise patterns. In contrast, in younger active patients, choosing to forgo ACL reconstruction or meniscal repair may lead to persistent instability and joint pain, and may also lead to initiation of degenerative arthritis if they are unwilling to change sport-related acquired activities. Arthroscopic surgery can be performed once the swelling and inflammation have subsided after the injury and the patient can return to essentially their original range of motion. If the ACL is completely damaged, it must be replaced with a graft. The graft can be taken from the patient’s own knee, which is called an autograft, or from a donor, which is called an allograft, or an artificial ligament can be used. Autograft sources include bone-patellar tendon-bone graft, N-cord tendon graft or quadriceps tendon graft, and if an autograft is applied, an incision will be made to take the tendon. The recovery time for ACL reconstruction is variable and is approximately 6-9 months, after this time, the sport can return to intense exercise. During this time, the patient participates in a rehabilitation program that restores range of motion, builds muscle strength, and regains balance and sports-related skills. The goal of treatment for meniscal injuries is to preserve the structure, and the function of the meniscus is to transmit stresses through the knee joint. Depending on the type of injury, the injury, the quality of the torn meniscus fragment, and the age of the patient, the doctor’s first consideration is to repair the meniscus. Studies have shown that if an athlete’s injury cannot be repaired, they have a high risk of damaging the cartilage and even developing arthritis very early. If possible, doctors apply a variety of techniques to suture the torn meniscus. The suturing is also done arthroscopically. If the meniscus cannot be repaired due to the damage of the meniscus, the type of tear, the poor quality of the tissue, or the lack of blood supply, the meniscus will be partially removed, called a partial meniscectomy, to preserve as much of the normal meniscus as possible. In some cases, if the tear is severe and complex, the surgeon may remove most of the meniscus. In these patients, a meniscal transplant is also indicated at a later date to organize the onset of degenerative arthritis. Approximately 70-90% of meniscus repairs are successful. Interestingly, those patients who had both meniscus and ACL damage, both treated at the same time, had a higher success rate. The reason for this may be that when the ACL reconstruction was done, there were bone tracts on the tibial and femoral side, and there was a small amount of bleeding in these tracts, and the blood carried factors that facilitated the healing of the meniscus. The time required for surgical recovery varies from about 3-6 weeks for partial meniscectomy and 12-16 weeks for meniscal repair, and the patient will have a rehabilitation program during this period. In cases of ACL reconstruction, the application of bone conduction screws may accelerate healing and create a secure joint. As was done with the meniscus, a growth factor scaffold is created to regenerate the ACL so that a graft is not applied. In addition to ACL reconstruction and meniscal repair, arthroscopic surgery is also used to reconstruct other ligaments that support the joint, regenerate articular cartilage, and relieve the symptoms of arthritis such as rattling and interlocking. Using arthroscopic techniques, the surgeon is able to fill in defects and remove free tissue fragments. By and large, arthroscopy can also treat knee osteoarthritis. Arthroscopic surgery in orthopedic cases can also be combined with incisional surgery to treat fractures. If the knee is fractured, the application of arthroscopy allows the fracture to be seen without disturbing the joint, enabling the placement of bone blocks and, if necessary, steel pins, screws or wires. If you decide to have arthroscopic surgery, it should be done by a qualified surgeon. A general orthopedic surgeon is fine for arthroscopic diagnosis, but for procedures such as ligament reconstruction, meniscal repair, meniscal transplantation and cartilage reconstruction, specialized training in sports medicine or arthroscopic surgery is required.