Head Injuries in Professional Football (Soccer)

Abstract

Introduction: Head injuries in sports may have been an underestimated health risk for many years. However, they potentially bear the risk of serious long-term sequelae with a potential impact on the athletes’ activities of daily living, sports, or career. Although the incidence of head injuries in professional football (soccer) is relatively low in comparison to so-called high-risk sports such as American football, rugby, boxing, or ice hockey, absolute numbers are substantial because of the high popularity of this sport and the large number of players. In 2006, a first step towards head injury prevention in football was made by altering a rule: henceforth intentional elbow to head contacts had to be punished by a red card. This action determined one of the three aims of this thesis: i) to present incidence rates of head injuries including their time trends and injury mechanisms; ii) to identify circumstances of head injury incidents, the behavior of referees, and their decisions; and iii) to investigate the effect of the rule change on the reduction of head injuries in professional male football. Methods: i) To investigate the time trends of head injuries, an analysis of head injuries in the 1st German Bundesliga was generated comprising the 11 consecutive seasons (2006/07 to 2016/17) following the rule change. The head injury database was based on continuously published data from the German football magazine “kicker Sportmagazin®” and other media sources. Injury mechanisms were analysed from video recordings. Injury incidence rates (IR) and 95% confidence intervals (95% CI) were calculated. Time trends were analysed via linear regression. ii) To identify circumstances of head injury incidents, the video analyses of all head injuries from 13 consecutive seasons (2000/01 to 2012/13) were screened. iii) To provide a description of injury mechanisms of head injuries and the effect of the rule change, the database of all head injuries comprising seasons 2000/01 to 2012/13 were screened and the equal number of seasons before and after the rule change were compared. Head injury mechanisms were analysed from video recordings. IRs and 95% CI as well as incidence rate ratios (IRR) to assess differences in injury rates six seasons before and six seasons after the rule change were calculated. Results: i) During the 11 consecutive seasons, 238 head injuries occurred during matches (IR 1.77 per 1000 match hours). There were no significant seasonal changes (expressed as annual average year-to-year change) in IRs over the 11-year period for total head injuries, facial and head fractures, head and face lacerations and abrasions, and head contusions. The average year-toyear increase for concussion was 6.4%. There were no seasonal changes in head injury mechanisms over the study period. ii) Most head injury incidents involved two players. Those players who suffered a subsequent head injury predominantly jumped (60%), headed the ball (36%), and ran forwards (20%), whereas the non-injured players mainly jumped (64%), headed the ball (27%), and raised the elbow to the head (23%). Free ball situations (two players challenging/dueling for the ball) caused the largest proportion of the head injuries (81%). iii) 356 head injuries were recorded (IR 2.22 per 1000 match hours) in 13 consecutive seasons. Contact with another player resulted in the greatest proportion of head injuries, especially head to head (34%) and elbow to head (17%) contacts. After the rule change the total number of head injuries was reduced by 29%. The subcategories head and face lacerations and abrasions declined by 42%, concussions by 29%, head contusions by 18% and facial and head fractures by 16%. Discussion/Conclusion: The first study in this thesis revealed that the subcategory concussion increased slightly over the (2006/07 to 2016/17) seasons, which could be the result of increasing match dynamics and/or a raised awareness for this injury type among team physicians and players. Total head injuries and the other subcategories remained reasonably stable over 11 consecutive seasons. The second study showed that heading duels are particularly associated with head injuries and could be target of future prevention strategies. The third study provided evidence that the incidence rates for total number of head injuries and their respective subcategories were lower in the six seasons after the rule change compared to the equal number of seasons before. Therefore, rule changes in football appear to be effective in reducing the occurrence of head injuries. To summarize, the increasing number of concussions requires action. Ongoing monitoring and surveying of head injuries allows practitioners to keep track of head injuries. For future research, the development of preventative measures to avoid potential (serious) health consequences of head injuries is warranted.