Prevention of knee injuries and ACL ruptures Systematic review and recommendations of the the German Knee Society (DKG): The Stop-X program

AIMS AND OBJECTIVES: Introduction Knee injuries and especially anterior cruciate ligament (ACL) tears are frequent in athletes. Therefore, primary and secondary prevention of sports-related lower limb injuries is an ongoing topic of interest. The aim of present study was to establish guidelines for the prevention of knee and ACL injuries on the basis of evidence-based concepts represented in current literature. METHODS: A comprehensive literature review regarding prevention programs for knee and ACL injuries was conducted. RESULTS: Several modifiable and non-modifiable risk factors for knee injuries in athletes have been reported in literature. Referring to the ACL, specific injury mechanisms have been identified and are well understood. In particular, it has been demonstrated that dynamic valgus is one of the most important modifiable risk factors. Simple tests like the drop jump test have shown their efficacy in screening and detecting athletes at risk. There is only little evidence for the preventive effect on knee and ACL injuries by single exercises. However, in order to prevent or correct endangering movement patterns including dynamic valgus, several complex prevention programs have been developed in the past. These prevention programs are included in standard warm-up exercises and are focusing on muscle strength, balance, and proprioception, as well as running and flexibility. It is reported that these training programs can reduce the incidence of knee injuries by up to 27% and ACL injuries by up to 51%. CONCLUSIONS: Screening, identification, and correction of endangering movement patterns like the dynamic valgus are the first crucial steps in order to prevent knee and ACL injuries in athletes. Furthermore, jumping, running and flexibility exercises as well as balance and strength training are proven to reduce the incidence of these injuries and should, therefore, be integrated into the regular warm up program. Appropriate complete prevention programs are freely accessible via the Internet and should be adapted to the specific sport disciplines