The epidemiology of head impacts, head injury assessments, and concussions in the National Rugby League: A study from the SCRIMMAGE database.

OBJECTIVES: Rugby League is a popular collision sport with an inherent risk of concussion. Management systems have been introduced at the elite level to detect and manage head impacts with the potential for concussion; however, little is known about the epidemiology of these events. This study aimed to describe the risk and incidence of head impacts, head injury assessments, and concussions in the National Rugby League. DESIGN: A retrospective cohort study. METHODS: Official National Rugby League player data from the 2017 to 2023 seasons was linked to the SCRIMMAGE registry of head impacts, to provide a definitive database of exposure (match participation, player-match hours) and outcomes (head impacts, head injury assessments, and concussions). The risk and incidence of each outcome were calculated, overall and across each season. RESULTS: Between 2017 and 2023 892 individual players participated in at least one game, with a total of 48,113.45 exposure hours. There were 5274 head impacts detected, resulting in 1849 head injury assessments, and 665 concussions. Incidence rates of head impacts, head injury assessments, and concussions per 1000 player-match hours were 109.62 (95% confidence interval: 103.47-116.13), 38.43 (95% confidence interval: 35.55-41.55), and 13.82 (95% confidence interval: 12.54-15.23) respectively. CONCLUSIONS: Head impacts, head injury assessments, and concussions were common events in National Rugby League, but occurred at comparable, or relatively lower, rates than similar collision sports. This burden of injury justifies the comprehensive National Rugby League concussion management system and supports ongoing efforts to mitigate the risk of head impacts, balanced against sporting considerations.