Epidmiological comparision of ACL injuries on different playing surfaces in high school football and soccer.
Ngatuvai MS, Yang J, Kistamgari S, Collins CL, Smith GA. Orthopaedic Journal of Sports Medicine. May 2022. doi:10.1177/23259671221092321
In a nationally representative sample, anterior cruciate ligament (ACL) injuries in high school football and soccer players were more likely to occur on artificial playing surfaces compared to natural playing surfaces.
Several investigations into the epidemiology of ACL injuries on different playing surfaces have led to conflicting evidence. Furthermore, many studies have focused on professional or collegiate athletes.
The researchers completed an epidemiological study of high school football and soccer to compare the number of ACL injuries on artificial turf versus natural playing surfaces.
The research team analyzed data collected through the National High School Sports-Related Injury Surveillance Study from 2007-08 to 2018-19 academic years. This study collected data from a nationally representative sample of high schools. The athletic trainer at each high school entered the data into the online reporting platform. For the current study, the authors defined an ACL injury as an injury that occurred during a school-sanctioned football or soccer practice or competition that (1) required medical attention and (2) resulted in at least 1 day of restricted activity. A single-athlete exposure was defined as an athlete participating in 1 practice or competition. Injuries were then categorized as either occurring on artificial turf or natural playing surfaces. The authors lacked information on how many times athletes played on artificial turf or a natural playing surface. Hence, they calculated a ratio between ACL injuries on each playing surface divided by the total number of injuries on each playing surface (ACL-turf/total-turf: ACL-natural/total-natural).
Over 12 years, the authors estimated that 389,320 ACL injuries occurred nationally in high school football and soccer athletes. A football player was ~23% more likely to experience an ACL injury on artificial turf than on natural grass. A soccer player, regardless of sex, was ~53 to 65% more likely to have an ACL injury on artificial turf than on natural grass.
The authors found that artificial turf related to a higher proportion of all injuries being an ACL injury compared to grass. The authors highlight that some of these relationships lacked statistical significance. However, if you look at the estimated proportion of ACL injuries, the differences may be clinically significant. For example, if we think it is meaningful that football had a higher proportion of ACL injuries on turf (1.23), we may also want to be concerned that boys’ soccer had a higher ratio, despite failing to reach statistical significance (1.65). We should interpret this method of comparing ACL injuries on artificial turf to natural grass carefully. Ideally, we would want to look at ACL injuries per session (practice/competition) on each playing surface instead of the number of ACL injuries per the total number of injuries on each playing surface. The current results could be tricky to interpret if the playing surface could influence the number of total injuries. Still, the playing surface seems to play some role in the epidemiology of ACL injuries. Clinicians and researchers should continue to explore how playing surface influences injuries at their facilities and nationally.
While the decision to install artificial surfaces is multifactorial, clinicians should be sure to communicate the latest evidence about the impact of playing surfaces on injuries to those involved in the decision making. Furthermore, clinicians that have artificial playing surfaces could encourage injury prevention programs, ensure the proper equipment is available onsite, as well as monitor injury rates for internal purposes and potentially share with the broader sports medicine community.
Questions for Discussion
Have you seen a difference in the prevalence of ACL injuries on various playing surfaces? If so, how have you tried to address this disparity?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban
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In my limited experience on both types of fields I will say that I have seen more ACLs torn on a turf field. I think several factors can lead to this including the length of the turf. Our football field has longer turf that looks more natural but seems to have higher incidence rates of non-contact ACL tears. As opposed to our softball field which has very short turf so the ball is a bit more reactive. While they are two total different sports, softball cleats tend to be metal and a bit longer than football cleats which would lead some to believe it would be more conducive to the cleat getting stuck which can lead to an ACL tear. Most of the ACL tears I have seen on natural grass occur from contact. I’d be interested to see if any studies have been conducted about the correlation to the length of the turf and ACL incidence rates.
Justin, Thank you for the great comment! This was something that I thought about as well. Not being a turf expert, I have worked with various sports on turf and have seen a number of variations. I think that while we continue to work on the question of turf vs. grass, I think a parallel track of comparing variations in turf would also be very informative.
I believe that athletes do get injured more on artificial l turf than grass when playing. I think it would be very beneficial to look at ways to try and prevent or look at the certain movements that occur when playing on the turf. I agree with the article when it says we should look at it during practices or games to see if there is a difference. I do believe that turf has a greater amount of force/friction and athletes tend to state they feel like their “foot gets caught”.
Hi Alexis, thank you for the comment! I think in-line with what Justin has said, that there more to this question for sure. I also am very curious to know more about how athletes transition from 1 playing surface to another. Have you had any indications that an athlete might get use to playing on 1 surface? I wonder if a transition to another surface, like an away game, would be particularly concerning.