Eight clinical conundrums relating to anterior cruciate ligament (ACL) injury in sport: recent evidence and a personal reflection.

Over two million anterior cruciate ligament (ACL) injuries occur worldwide annually, and the greater prevalence for ACL injury in young female athletes is one of the major problems in sports medicine. Optimal treatment of ACL injury requires individualised management. Patient selection is of utmost importance, and so is respect for the patient's functional demands and interests. All patients with an ACL tear may not need surgery, however athletes and persons with an active lifestyle with high knee functional demands including cutting motions need and should be offered surgery. In many cases it may not be the choice of graft or technique that is the key for success, but the choice of surgeon. The surgeon should be experienced and use a reconstructive procedure he/she knows very well and is comfortable with. The development of osteoarthritis after an ACL injury depends very much on the injury mechanism and concurrent meniscal injury, as knee articular cartilage continues to heal for 1-2 years after an ACL injury. Therefore the surgeon and rehabilitation team must pay attention to the rehabilitation process and to the decision when to return to sport. Return to sport must be carefully considered, as top-level sport in itself is one main risk factor for osteoarthritis after ACL injury. The present criteria for return to sport need to be revisited, also due to the fact that recurrent injury seems to be an increasing problem. ACL injury prevention programmes are now available in some sports. The key issue for a prevention programme to be successful is proper implementation. Vital factors for success include the individual coaching of the player and well controlled compliance with the training programme. Preventive activities should be more actively supported by the involved athletic community. Despite substantial advances in the field of ACL injury over the past 40 years, substantial management challenges remain.