The injury of Chinese woman Wang Xin, who was accidentally injured in the bronze medal match of women’s singles in the London Olympic Games, has been determined and she will go to Germany for surgery for a ruptured anterior cruciate ligament in her left knee. So what is an ACL injury and how can it be treated? Here we have a brief introduction to ACL injuries. What is an ACL injury The ACL, also known as the anterior cruciate ligament, is located in the knee joint and connects the femur to the tibia, its main role is to limit the excessive forward displacement of the tibia, it works with other structures in the knee joint to maintain the stability of the knee joint, allowing the body to perform a variety of complex and difficult lower limb movements. The literature reports that the incidence of ACL rupture in the general population in the United States is approximately 1/3000, while the annual incidence of ACL rupture in soccer players is 60/100,000. A survey of active athletes in China found that the incidence of ACL rupture was 0.43%. Sports with physical impact or high speed are prone to ACL rupture. Commonly injured actions such as soccer with the opposing player’s foot to occur external rotation injury, basketball with the ball over the knee joint of the supporting leg occurs when the rapid twisting occurs external rotation injury, after shooting a basketball single leg landing sprain, skiing sports, high-speed decline when the skateboard into the snow, the athlete was tripped over the occurrence of hyperextension injury, are prone to lead to ACL injury. Some mass sports, such as tug of war, vaulting, box jumping, etc. are also prone to ACL injuries. ACL injuries can also occur in high-energy traffic accidents involving pedestrians, falls on electric bicycles, or inadvertent falls in people who are physically weak. What are the clinical manifestations of ACL injury? 1. When the ligament is torn, it is accompanied by tearing sound and joint misalignment, intra-articular hemorrhage, resulting in joint swelling, pain, and most of them cannot continue to engage in the original movement, and even have limited extension and hyperflexion activities; 2. continuous interruption, visible stump, lateral wall of the intercondylar fossa of the femur or posterior femoral epicondyle and corresponding bone contusion manifestation of the tibial plateau. 4, joint laxity and instability, the patient has a sense of knee joint misalignment or playing soft leg in sports, cannot stop and turn sharply, and cannot use the affected leg for single leg support; 5, the knee joint is easily and repeatedly sprained and painful during sports, causing even repeated interlocking after meniscus injury. There is a general consensus on whether ACL rupture requires surgical treatment. For patients under 40 years of age with high sports and walking requirements, active ligament reconstruction is advocated to restore athletic ability. In older patients or those with lower motor requirements, conservative treatment with muscle strength strengthening exercises and use of joint stabilization protection devices is possible. Of course, age is not an absolute factor. The best treatment option for complete rupture of the ACL is surgical reconstruction of the ACL; arthroscopic ACL reconstruction is a mature technique with little trauma and fast recovery; the current surgical methods for ACL reconstruction include: single-bundle reconstruction, double-bundle reconstruction, etc.; there is no significant difference between the clinical results of the two procedures. The graft materials that can be used to reconstruct the ACL include: autologous materials, such as N cord tendon, autologous patellar tendon, etc., with the best results. If multiple ligaments are injured at the same time, you can consider adding allograft tendons or artificial ligaments, etc.; 6. The fixation materials that need to be used to reconstruct the ACL include: metal interface screws, absorbable interface screws, EndoButton, Introfix, etc.; What are the consequences and complications of untimely diagnosis and treatment of the ACL? ACL rupture without timely treatment or repeated sprains can easily lead to secondary damage to the knee joint 1. Injury to the medial and lateral meniscus of the knee joint. The meniscus is a crescent-shaped fibrocartilage in the knee joint, located between the joint surface formed by the tibia and femur, increasing the contact area between the femoral condyle and tibial plateau, thus increasing knee joint stability. After the rupture of the ACL, the existence of anterior instability of the knee joint, especially repeated sprains, causes contradictory movements of the meniscus, which in turn leads to secondary injuries of the meniscus. 2. Knee joint cartilage injury. Long-term instability and repeated sprains lead to degenerative changes in the knee joint including patellofemoral articular cartilage and medial and lateral intervertebral cartilage. 3, Bone flab formation and chronic synovitis. The end result of knee degeneration leads to the development of osteoarthritis, especially the formation of osteoid at the edge of the cartilage in the intercondylar fossa, as well as intercondylar spine hyperplasia.