The ACL reconstruction procedure is performed when severe knee instability (3rd degree) is found, which makes it difficult for active people to function normally. The aim of the treatment is to improve the quality of life and to prevent the rapid development of knee osteoarthritis. Surgical ACL reconstruction is especially recommended for athletes and blue-collar workers. Less degrees of ACL damage and complete rupture of the ACL ligament in people leading a sedentary lifestyle can be successfully treated conservatively through specialized rehabilitation.