Mechanisms of anterior cruciate ligament injury across sports: A systematic review and meta-analysis of video-based studies.

Purpose

This systematic review and meta-analysis aimed to investigate anterior cruciate ligament (ACL) injury mechanisms across sports by quantifying the prevalence of direct-contact, indirect-contact and non-contact injuries and identifying the sport-specific activities most commonly associated with these mechanisms.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, MEDLINE, Embase and the Cochrane Library were searched from January 2000 through August 2025. Eligible studies included skeletally mature athletes with primary ACL injuries in whom injury mechanisms were assessed through video analysis. Overall, 1333 athletes were included (79.4% male, 19.1% female; sex not reported in 1.5%), with a weighted mean age of 25.3 ± 4.6 years. Contact mechanisms were classified as direct contact (force applied directly to the knee), indirect contact (external force applied to another body region leading to knee loading) or non-contact (no external force). Activity was defined as the sport-specific task at the time of injury; quantitative hip, knee or ankle kinematics were not assessed.

Results

Twenty-six studies were included. Overall, 45.1% of ACL injuries were non-contact, 41.0% indirect-contact and 18.5% direct-contact. Basketball players had a higher risk of indirect-contact injuries (odds ratio [OR], 1.34; 95% confidence interval [CI], 1.21-1.49), whereas rugby and American football players showed greater odds of direct-contact injuries (OR, 1.16; 95% CI, 1.04-1.31). Non-contact injuries were most frequent in handball, netball and skiing (OR, 1.29; 95% CI, 1.11-1.49). Activity analysis showed that ACL injuries most commonly occurred during jump landings and speed-related movements, with basketball players at increased risk during jump take-off and change-of-direction tasks.

Conclusion

ACL injury mechanisms differed substantially across sports. Basketball was predominantly associated with indirect-contact injuries, rugby and football with direct-contact mechanisms, and handball, netball and skiing with non-contact injuries. Prevention programmes should integrate universal neuromuscular training with sport-specific components targeting the dominant injury mechanisms of each discipline.

Level of evidence

Level IV, systematic review and meta-analysis.