Return to Competition and Career Sustainability After Primary ACL Reconstruction in Football: A Nationwide Cohort Study of Long-Term Participation

BACKGROUND: Return to competition (RTC) after anterior cruciate ligament reconstruction (ACLR) is frequently reported, but long-term football participation following return remains poorly described. OBJECTIVE: The aim was to describe RTC rates after primary ACLR in football players and to evaluate post-RTC career sustainability, quantified by the number of matches and seasons played, across sex, age, and pre-injury level. METHODS: In this decade-long nationwide cohort study, football players undergoing primary ACLR between 2014 and 2023 were identified in the Swedish Knee Ligament Registry and linked to the Swedish Football Association's match database. RTC was defined as participation in one or more official match after surgery. Analyses of post-RTC match and season participation were restricted to players who returned by the 2022 season or earlier, allowing a minimum potential follow-up of three seasons. Outcomes were compared across sex, age groups, and pre-injury level using non-parametric methods. RESULTS: A total of 10,836 football players were included, of whom 6339 (58.5%) achieved RTC. RTC rates varied across pre-injury competitive levels, ranging from 90.4% at the top level to 35.9% at the recreational level (p < 0.001). Among players with sufficient follow-up (n = 4749), median post-RTC participation was 31 matches (interquartile range [IQR] 11-70) across three seasons (IQR 2-5). Men accumulated more matches after RTC than women (33 vs 29; p = 0.017) and remained active for more seasons (4 vs 3; p < 0.001). Pre-injury competitive level was strongly associated with career sustainability (p < 0.001): top-level players accumulated a median of 97 matches (IQR 42-148) across five seasons (IQR 3-6), whereas players competing at lower levels accumulated fewer matches and seasons. Age-related differences were significant in men but not in women. CONCLUSION: Football career sustainability following primary ACLR was greatest among players competing at higher pre-injury levels and, to a lesser extent, among men. Although RTC was commonly achieved, long-term participation after return was often limited, indicating that RTC alone provides an incomplete description of football participation after ACLR.