ACL has the function of limiting excessive tibial anterior displacement, controlling tibial rotation and proprioceptors, etc. Its damage can directly cause knee instability and functional decline, which in turn can lead to meniscal and cartilage degeneration, resulting in early-onset osteoarthritis and seriously affecting patients’ quality of life. It has become a consensus to repair and reconstruct damaged ligaments through surgical transplantation. Autologous ligament grafts are considered the “gold standard” for ACL reconstruction and repair, however, the use of autologous grafts such as the hamstring tendon and N-cord tendon can cause complications such as decreased muscle strength and anterior knee pain in the donor area, therefore, at this stage, the use of specialized bone bank-treated allograft ligament grafts is still the more common method. However, allografts need to undergo a “ligamentization” process of necrosis, revascularization, cell ingrowth and collagen remodeling for more than 12 months, which prolongs the patient’s recovery time. Especially in the early stages of ligament implantation, the tendon-to-bone healing is significantly slower than bone-to-bone healing due to the absence of bone at the ends of the tendon graft alone and the fixation of the tendonous portion in the bone tunnel. Also because of the lack of bony support the grafts are mostly in eccentric position and the flat ligament at the tunnel opening will undergo anterior-posterior oscillation generating friction and easily damage the transplanted tendon. Therefore, how to improve the tendon-bone healing has become an issue of interest to scholars. The site of normal tendon-bone union, also known as the attachment point or stop, is the site where the tendon, ligament, or joint capsule contacts the bone, and is divided into direct and indirect stops according to the structure. A normal ACL stop has a typical direct stop structure, with ligament-fibrocartilage-calcified cartilage-bone from the ligament toward the stop, with a tidal line separating the fibrocartilage from the calcified cartilage. The indirect stops are connected by collagen fibers (i.e., Sharpey’s fibers) between the grafted tendon and the bone tunnel. Conventional ACL reconstruction involves placement of the grafted tendon into the punched bone tunnel, hopefully allowing for a possible indirect stop for tendon-bone healing. Thus, the way the ligament is placed in the bone tunnel determines the success or failure of the ACL reconstruction procedure. Typically, there are two main ways in which simple ligament grafts move within the bone tunnel: one is the movement of the graft along the longitudinal axis of the tunnel (i.e., the pulling rubber band effect), which refers to the longitudinal stretching of the graft within the bone tunnel during knee flexion and extension; the other is the movement of the graft perpendicular to the tunnel axis (i.e., the wiper effect), which refers to the anterior-posterior oscillation of the graft within the bone tunnel during knee flexion and extension. Neither approach is conducive to a firm union between tendon bones. Moreover, regardless of the “firm graft tendon fixation”, the gap between the ligament and the bone tunnel does not effectively prevent the rubber band pulling effect and the wiper effect. Some scholars have attempted to improve the tendon-bone interface by modifying the size of the bone tunnel. However, there are obvious two sides to the results of related studies. On the one hand, it has been found that the smaller the diameter of the bone tunnel, the more dense and mature the collagen fibers of the tendon-bone connection, and it is believed that the size of the bone tunnel should be roughly the same as the diameter of the graft during ACL reconstruction. At the same time, it was found that when the diameter of the graft was the same as the diameter of the bone tunnel, every movement of the joint caused a small movement of the graft in the bone tunnel, which caused friction and led to osteolysis and eventually enlargement of the bone tunnel. Since then, surgeons have also tried to obtain better healing by adjusting the position and length of the tunnel during surgery, enhancing the starting tension and fixation of the graft tendon, and other corresponding surgical techniques. However, it was difficult to create an early, good biological healing between the graft and the bone tunnel. It has been found that bone ingrowth towards the tendon predominates in the process of tendon-bone healing, and the biomechanics of the tendon-bone interface is closely related to the degree of ingrowth and mineralization of the new bone. Therefore, accelerating bone ingrowth around tendon grafts is the key to improving tendon-bone healing. It is well known that the rate of bone-to-bone ingrowth is much faster than the rate of bone ingrowth into the tendon. Through years of research on allogeneic bone grafts, our group proposes to use allogeneic Achilles tendon with heel bone as the graft, in order to obtain better ACL reconstruction results by preserving the naturally formed tendon stop structure between the allogeneic tendon and the allogeneic bone on the one hand, and taking advantage of the bone-to-bone ingrowth on the other hand. Through the follow-up study of this group of cases, we found that ACL reconstruction using allograft Achilles tendon with heel bone can reduce the rate of bone tunnel enlargement and promote tendon-bone healing to a certain extent compared with ACL reconstruction using allograft tendon alone, and the recent efficacy is better. Compared with allograft tendon alone, allograft bone has better osteoconductivity and is more conducive to host bone ingrowth, which greatly shortens the graft-host union time and enables early healing. In addition, because the allograft bone and the host bone at the implantation site pass through the cancellous bone structure, the degree of union between the two is much tighter than that between the ligament and the bone tissue alone, which greatly improves the stability of the initial implantation and is more conducive to the early integration of the reconstructed structure and the formation of a virtuous circle. The allograft tissues used in this study are all deep cryogenic frozen products provided by the bone bank of the First Affiliated Hospital of the PLA General Hospital, which has a stable quality and greatly reduces the immunity of the allograft bone, reducing the incidence of immune rejection and providing a good effect with half the effort.