The epidemiology of head impacts, head injury assessments, and concussions in the National Rugby League: 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 (HIA), and concussions in Australian National Rugby League (NRL).

Design

A retrospective cohort study.

Methods

Official NRL player data from the 2017 through 2023 NRL Premiership 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, HIAs, 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 NRL game, with a total of 48,113.45 exposure hours. There were 5274 head impacts detected, resulting in 1849 HIAs, and 665 concussions. Incidence rates of head impacts, HIAs, and concussions per 1000 player-match hours were 109.62 (95% CI: 103.47–116.13), 38.43 (95% CI: 35.55–41.55), and 13.82 (95% CI: 12.54–15.23) respectively.

Conclusions

Head impacts, HIAs, and concussions were common events in NRL, but occurred at comparable, or relatively lower, rates than similar collision sports. This burden of injury justifies the comprehensive NRL concussion management system and supports ongoing efforts to mitigate the risk of head impacts, balanced against sporting considerations.