One of the most common knee injuries is damage or rupture of the anterior cruciate ligament, or as it is often abbreviated in practice – ACL. The knee is the most complex joint in the human body. The anterior cruciate ligament is only one of the four ligament whose role is to stabilize the knee. The ACL is responsible for preventing excessive movement of the lower leg (tibia) in relation to the upper leg (femur). One of the more important roles of the anterior cruciate ligament is the prevention of knee hyperextension. Almost 70-80% of injuries to the anterior cruciate ligament occur without contact, that is the injury most often occurs during a sudden change in direction of movement or when landing on an outstretched leg where the knee assumes a valgus position. The most common symptoms of this injury are strong, sudden knee pain and instability knee joint. The tests performed to diagnose this injury are the Lachman test and the anterior drawer test. Reconstruction of the anterior cruciate ligament is performed arthroscopically and rehabilitation lasts six to eight months on average. During rehabilitation, the patient uses an orthosis. The aim of this final paper is to explain the anatomy of the knee and its importance in our daily life. In addition, the goal is to explain in detail the reconstruction of the anterior cruciate ligament and rehabilitation after injury. Rehabilitation consist of physiotherapeutic treatments and kinesitherapeutic exercise. This final paper is divided into six parts. The first part consists of an introduction. The second part explains the anatomy of the knee. The third part talks about injuries of ACL and the fourth part follows the third because it explains the diagnosis of the injury. The fifth part shows the rehabilitation that takes place in stages and the sixth part is the conclusion of this final work.