Impact of playing position on ACL injury characteristics, risk and career outcomes in football-An analysis of 742 cases of the anterior cruciate ligament registry in German football

To evaluate how playing position affects anterior cruciate ligament (ACL) injury features, incidence rates and career outcomes across competition levels in male football. Using the prospectively collected 'ACL Registry in German Football', we analysed six seasons (2016-2022) across professional (first to third leagues), semi-professional (fourth to sixth) and amateur (seventh) levels. In professional players, return-to-performance over five seasons was evaluated with linear mixed-effects models, and career outcomes within three seasons after injury were assessed. Injury mechanisms were examined across all levels. Outcomes were stratified by position (goalkeeper [GK], defender [DF], midfielder [MF], forward [FW]). A total of 742 ACL injuries were analysed (professional n&#x2009;=&#x2009;172, semi-professional n&#x2009;=&#x2009;316, amateur n&#x2009;=&#x2009;254). Among professionals, FWs showed the highest rate of a drop in competitive level (47.5%), and GKs a numerically higher rate (54.5%); however, the GK comparison was not statistically significant after correction for multiple testing and should be regarded as exploratory. Mixed-effects models for matches and minutes played showed significant main effects for time and position (all p&#x2009;<&#x2009;0.001) but no significant interaction (p&#x2009;=&#x2009;0.064 matches; p&#x2009;=&#x2009;0.105&#x2009;min). Match-related incidence was highest in DFs (0.397/1000 player-hours) and MFs (0.370). Injury mechanisms varied by level; direct contact accounted for 66.7% and 46.2% in professional FWs and DFs, respectively, whereas non-contact injuries predominated across all positions in amateur players. The characteristics and outcomes of ACL injuries may vary by position. Match-related injury rates tended to be highest for DFs and MFs, while career-altering effects appeared most pronounced in FWs, with an exploratory, non-significant tendency also for GKs. Injury rate and consequence should be considered separately. Although non-contact injuries are most common overall, direct contact injuries were relatively frequent among professional FWs and DFs. Prevention and rehabilitation strategies could be tailored to each position. Level II, prospective cohort study.