Anterior cruciate ligament reconstruction, the primary treatment for anterior cruciate ligament rupture, often suffers from poor rotational stability after surgery. To solve this problem, the understanding of the anterolateral ligament (ALL) has been deepened. 1, the anterior cruciate ligament rupture, an avulsed bone fragment, defined as a segond fracture, was often present on the anterolateral tibial plateau, which was then thought to be caused by excessive internal rotation and inversion of the knee joint at the time of the anterior cruciate ligament rupture, caused by the avulsion of the joint capsule. It was considered to be an indirect sign of ACL rupture. 2, In 1879, segond, in explaining the segond fracture, described in detail the fibrous strip connecting the lateral epicondyle of the femur to the anterolateral aspect of the lateral tibial plateau. 3, There are also different descriptions: lateral middle capsular ligament, lateral capsular ligament, lateral anterior 1/3 capsular ligament, anterolateral bundle, etc. 4, Recent studies have named it as the anterolateral ligament, but there are differences in the specific anatomical description. 5, It is believed that the tibial stop of ALL is more consistently located midway between the Gerdy node of the tibia and the head of the fibula. 6, The femoral stop is controversial: some believe it is located anteriorly and inferiorly to the lateral collateral ligament stop, while others believe it is located posteriorly and superiorly. 7, Camilo et al. concluded that the ALL is a fixed structure on the lateral aspect of the knee and that the femoral stop is located anterior to the femoral stop of the lateral collateral ligament, which varies above and below. In the tibial segment, it stops partly at the lateral meniscus and partly at the middle of Gerdy’s node and the fibular head. 8, Armin et al. concluded that ALL is a distinct anatomic structure on the anterolateral aspect of the knee, but is not fixed and occurs in about half of the population. It has a distinct bony stop, runs obliquely outside the joint capsule, is ligamentous in nature, differs from the capsule layer of the iliotibial bundle, and serves primarily to increase the rotational stability of the joint and prevent excessive internal rotation.