ACL stands for Anterior cruciate ligament and ACL Reconstruction refers to a type of surgery to replace the important ligament i.e. the anterior cruciate ligament (ACL) in the patient's knee. ACL injuries are the ones, which usually occur while playing sports especially the sports including quick direction changes, jumps, fast running and sudden stops e.g. volleyball, soccer, basketball, hockey, skiing, and football. ACL injuries happen when the ACL gets stretched and is resultantly teared off. ACL is an essential part of the knee as it helps in binding and keeping the knee stable. It is present between the tibia and the femur bones and prevents the slipping of the tibia. Its main function is to provide complete strength to the knee when the knee moves from one side to the other side. Damaging the ACL may result in discomfort or difficulty in playing sports, walking, jumping or running. Injury of ACL may take a lot of time to heal and requires continuous doctor consultations and physiotherapy. If the ACL damage is severe, the doctor will advise getting the ACL replaced through a surgical process especially in athletes and young people.