Surgery is necessary after a ruptured knee cruciate ligament injury. The previous method was to cut the knee and suture the injured ligament in the hope that the injured ligament would heal and restore stability to the knee joint. However, this method of suturing alone proved to be ineffective, and the patient would still have intolerable loosening of the knee joint after surgery, and the surgery was so damaging to the patient that this method of incision and suturing was eliminated. It has been replaced with an arthroscopically monitored surgical reconstruction, in which tendon tissue is taken from another part of the body to recreate a cruciate ligament. This method is less invasive and restores function to the knee faster than the previous method, which is called “minimally invasive treatment”. There are various methods such as single bundle reconstruction and double bundle reconstruction. The materials used for ligament reconstruction are autologous tendons, allograft tendons and artificial ligaments. Of course, among these materials, autologous tendon is the best, as it has no rejection after surgery, is easily viable, and heals easily with the bone. Although it is easy to heal, it can take at least a long year. Moreover, many patients still have some loosening after surgery, and the results are not as good as they should be, and some patients even need a second reoperation, especially after posterior cruciate ligament surgery. Even if most patients end up with clinically satisfactory results, it is difficult to reach the patient’s pre-injury state. This is because the human cruciate ligament itself is an irregular shape in order to adapt to the complex movement process of the human body, in order to ensure that the knee joint is always in a stable state during the movement, and that no anterior or posterior displacement occurs, without damaging the knee joint. The cruciate ligament itself also has proprioceptive organs that regulate the body’s posture at all times to prevent falls. The reconstructed ligament is different from the original ligament in morphology, even if it is double-bundle reconstruction, it does not reach the original anatomical form, and in the early post-surgery period, the tendon is still in a dead state, so there is no proprioceptive organ, so some patients always feel that their legs are not obedient after surgery, and they tend to play with weak legs. What is the best way to restore maximum function of the cruciate ligament? Of course there is. If you can preserve and suture the stretched damaged ligament on top of the surgical reconstruction, it will restore the function of the cruciate ligament to a greater extent. This is because the preserved cruciate ligament itself has blood flow and is alive, which will facilitate the survival of the reconstructed ligament. The preserved cruciate ligament itself has receptors for maintaining body balance, and when it is sutured and stretched, tension is restored and these receptors will function quickly. In addition, the reconstruction of the ligament also rapidly stabilizes the knee joint and facilitates the healing between the sutured injured ligament and the bone, and the healed ligament is the original ligament and its function is almost the same as before the injury. This approach should be the future direction of cruciate ligament injury treatment, and it has been reported that patients treated with disability-preserving reconstruction can achieve 100% restoration of knee stability.