Anterior cruciate ligament (ACL) injury is commonly seen in sports such as soccer, rugby, and skiing. Although many individuals initially recover well, the ongoing instability often prevents return to sports and leads to further knee injury, and the risk of developing future osteoarthritis becomes increased. Bracing is rarely sufficient. Surgical reconstruction performed early, within 3-6 weeks, helps to minimize the risk of further injury. ACL surgery should be treated as an urgent matter: assessment, diagnosis, and surgery can usually be completed within a few weeks. The athlete, elite, or weekend-warrior can then start early rehabilitation to maximize the benefits of the knee reconstruction.