Anterior cruciate ligament injuries of the knee are relatively common, with 200,000 cases reported in the United States each year, 100,000 of which require ACL reconstruction surgery. The main focus of current treatment approaches is not the indication for surgery, but rather the choice of graft. Familiarity with the anatomical and biomechanical characteristics of the ACL can help to understand the mechanism of injury and repair. Anatomy】 The anterior cruciate ligament is composed of collagen fibers arranged in longitudinal rows and surrounded by the intra-articular synovial membrane. The tibial stop is located at the tibial plateau, in the anterolateral recess in front of the tibial crest, and is located lateral to the anterior horn stop of the lateral meniscus. The ACL is 31-35 mm long and has a cross-sectional area of 31.3 mm2 The blood supply is mainly from the middle knee artery, to which the bony attachment zone provides little blood supply. It is innervated by the posterior joint nerve, a branch of the tibial nerve. There are mechanoreceptors on the surface of the anterior cruciate mandi ah, especially at the ligament stops (especially on the femoral side) and directly below the outer synovial sheath. Biomechanics】 The anterior cruciate ligament is the main structure that prevents the tibia from moving forward. In the flexed knee, the anterior medial bundle is tense and provides the main resistance to tibial anterior migration. In extended knee, the majority of the posterior external bundle is tense, providing the primary resistance to knee hyperextension. Rupture of the ACL occurs to varying degrees under different weight-bearing conditions and is largely dependent on the position of the bones at the time of injury and the forces exerted by weight-bearing. The complexity of the ACL arrangement and its response to weight-bearing is important in analyzing the results of tensile testing, and its maximum strength should not be a fixed value. Due to the presence of mechanoreceptors on the ACL, it has a proprioceptive function in addition to its mechanical function of limiting displacement.