Retrospective Cohort Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Nov 18, 2021; 12(11): 833-841
Published online Nov 18, 2021. doi: 10.5312/wjo.v12.i11.833
Preseason elimination impact on anterior cruciate ligament injury in the National Football League
Michael Patetta, Benjamin Mayo, Omar Zaki Martini, Breanna Sullivan, Leonard Onsen, Mark Hutchinson
Michael Patetta, Benjamin Mayo, Omar Zaki Martini, Breanna Sullivan, Leonard Onsen, Mark Hutchinson, Department of Orthopaedics, University of Illinois Chicago College of Medicine, Chicago, IL 60612, United States
Author contributions: All authors solely contributed to this paper.
Institutional review board statement: This study was exempt from institutional board review as it was conducted using publicly available information.
Informed consent statement: This study does not require informed consent statement.
Conflict-of-interest statement: None of the authors feature potential conflicts of interest nor have they received any sort of support to carry out this study.
Data sharing statement: No individual participant data was shared.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Omar Zaki Martini, BSc, Research Fellow, Department of Orthopaedics, University of Illinois Chicago College of Medicine, 835 S. Wolcott Avenue E270 MSS MC 844, Chicago, IL 60612, United States. omarti29@uic.edu
Received: June 6, 2021
Peer-review started: June 6, 2021
First decision: July 28, 2021
Revised: August 3, 2021
Accepted: September 15, 2021
Article in press: September 15, 2021
Published online: November 18, 2021
Abstract
BACKGROUND

Anterior cruciate ligament (ACL) injuries represent detrimental injuries in the National Football League (NFL). A significant portion of these injuries often occur in preseason exhibitions. The Coronavirus disease 2019 pandemic presented a unique disruption to preseason NFL football with the cancelation of all preseason games.

AIM

To compare the incidence of ACL tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons (2015-2019) and determine if there was any change in incidence with the elimination of the preseason.

METHODS

NFL players who suffered ACL tears during the preseason and first eight weeks of the NFL season from 2015-2020 were identified. The number of ACL injuries for the 2015-2019 seasons was compared to the 2020 season for four different timeframes. For each analysis, the cumulative number of ACL injuries to that time point was used to calculate the percent difference for descriptive analysis. Additionally, the number of teams with at least one player suffering an ACL tear were identified and compared using Chi-Squared testing. Finally, a cumulative relative risk was calculated for each week played.

RESULTS

There were 14 ACL tears through the first four games of the 2020 season, a 118.8% (14 vs 6.4) increase in comparison to the 5-year average over the first 4 regular season weeks of 2015-2019. However, when accounting for injuries occurring during the preseason from 2015-2019, there were 18.6% (14 vs 17.2) fewer total ACL injuries through regular season week 4 with no significant difference in percentage of teams impacted when these preseason injuries were accounted for P = 0.394. Results were similar (19 vs 17.2) over 8 total games played (whether regular season or preseason), and over 8 regular season games (P = 0.196, P = 0.600).

CONCLUSION

The elimination of the NFL preseason resulted in a higher rate of injuries during the first 4 games of the regular season. However, these increases are offset by the injuries typically sustained during the preseason. This suggests there may be front-loading of injuries over the course of an NFL season, such that players may be more prone to injury when the intensity of play suddenly increases, whether in the preseason or regular season.

Keywords: Anterior cruciate ligament, National football league, Player safety, Ligamentous injury, Preseason, COVID-19

Core Tip: The coronavirus disease 2019 pandemic presented a unique disruption to preseason National Football League (NFL) football with the cancelation of all preseason games. This study compared the incidence of anterior cruciate ligament (ACL) tears through the first eight weeks of the NFL season in 2020 to the mean incidence over the previous 5 seasons and found that there was indeed an increase in ACL tears through the first four games of the 2020 season with no significant difference when accounting for the preseason. This suggests that there may be front-loading of injuries over the course of an NFL season. In summary, this study suggests that if preseason games are eliminated, players can expect similar rates of ACL tears overall when compared to conventional seasons, but with more ACL tears in the first four weeks of the regular season.