An analysis of specific lower extremity injury rates on grass and FieldTrf playing surfaces in National Football League games:​ 2000-2009 seasons

Hershman, Elliott B.; Anderson, Robert; Bergfeld, John A.; Bradley, James P.; Coughlin, Michael J.; Johnson, Robert J.; Spindler, Kurt P.; Wojtys, Edward; Powell, John W.

Affiliations

¹Department of Orthopaedic Surgery, Lenox Hill Hospital, North Shore-LIJ Orthopaedic Institute, North Shore-LIJ Healthcare System, New York, New York

²Department of Orthopedic Surgery, Carolinas Medical Center and OrthoCarolina, Charlotte, North Carolina

³Department of Orthopaedic Surgery, Cleveland Clinic, Cleveland, Ohio

⁴Department of Orthopedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania

⁵Oregon Health Science University Division of Orthopedic Surgery & Rehabilitation, Portland, Oregon, and Coughlin Foot & Ankle Clinic, Boise, Idaho

⁶Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont

⁷Vanderbilt University, Vanderbilt Sports Medicine, Nashville, Tennessee

⁸Department of Orthopedic Surgery, University of Michigan, Ann Arbor, Michigan

⁹Med Sports Systems, Dimondale, Michigan

Abstract and keywords

Background: Players in the National Football League (NFL) sustain injuries every season as the result of their participation. One factor associated with the rate of injury is the type of playing surface on which the players participate.

Hypothesis: There is no difference in the rate of knee sprains and ankle sprains during NFL games when comparing rates of those injuries during games played on natural grass surfaces with rates of those injuries during games played on the artificial surface FieldTurf.

Study Design: Descriptive epidemiology study.

Methods: The NFL records injury and exposure (ie, game) data as part of its injury surveillance system. During the 2000-2009 NFL seasons, there were 2680 games (5360 team games) played on grass or artificial surfaces. Specifically, 1356 team games were played on FieldTurf and 4004 team games were played on grass. We examined the 2000-2009 game-related injury data from those games as recorded by the injury surveillance system. The data included the injury diagnosis, the date of injury, and the surface at the time of injury. The injury data showed that 1528 knee sprains and 1503 ankle sprains occurred during those games. We calculated injury rates for knee sprains and ankle sprains—specifically, medial collateral ligament (MCL) sprains, anterior cruciate ligament (ACL) sprains, eversion ankle sprains, and inversion ankle sprains—using incidence density ratios (IDRs). We used a Poisson model and logistic regression odds ratios to validate the IDR analysis. A multivariate logistic regression model was used to adjust the odds ratio for weather conditions.

Results: The observed injury rate of knee sprains on FieldTurf was 22% (IDR = 1.22, 95% confidence interval [CI], 1.09-1.36) higher than on grass, and the injury rate of ankle sprains on FieldTurf was 22% (IDR = 1.22, 95% CI, 1.09-1.36) higher than on grass. These differences are statistically significant. Specifically, the observed injury rates of ACL sprains and eversion ankle sprains on FieldTurf surfaces were 67% (P < .001) and 31% (P < .001) higher than on grass surfaces and were statistically significant. The observed injury rates of MCL sprains and inversion ankle sprains were also not significantly higher on FieldTurf surfaces (P = .689 and .390, respectively).

Conclusion: Injury rates for ACL sprains and eversion ankle sprains for NFL games played on FieldTurf were higher than rates for those injuries in games played on grass, and the differences were statistically significant.

Keywords: injury epidemiology; artificial surfaces; ankle sprains; knee sprains

Links

DOI: 10.1177/0363546512458888

PubMed: 22972855

WoS: 000309351000006

History

Online: 2012-09-12

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Cited By (12)

Year	Entry
2016	Magill ME, Anderson RB. American football. In: Valderrabano V, Easley M, eds. Foot and Ankle Sports Orthopaedics. Cham, Switzerland: Springer International Publishing; 2016:413-420.
2019	Mack CD, Hershman EB, Anderson RB, Coughlin MJ, McNitt AS, Sendor RR, Kent RW. Higher rates of lower extremity injury on synthetic turf compared with natural turf among National Football League athletes: epidemiologic confirmation of a biomechanical hypothesis. Am J Sports Med. January 2019;47(1):189-196.
2020	Mack CD, Kent RW, Coughlin MJ, Shiue KY, Weiss LJ, Jastifer JR, Wojtys EM, Anderson RB; NFL Musculoskeletal Committee. Incidence of lower extremity injury in the National Football League: 2015 to 2018. Am J Sports Med. July 2020;48(9):2287-2294.
2019	Kent RW. Footwear and injury prevention in elite American football. Footwear Sci. 2019;11(suppl 1):S7-S8.
2013	Drakos MC, Taylor SA, Fabricant PD, Haleem AM. Synthetic playing surfaces and athlete health. J Am Acad Orthop Surg. May 2013;21(5):293-302.
2021	Kent R, Yoder J, O'Cain CM, Meade Spratley E, Arbogast KB, Sorochan J, McNitt A, Serensits T. Force-limiting and the mechanical response of natural turfgrass used in the National Football League: a step toward the elimination of differential lower limb injury risk on synthetic turf. J Biomech. October 11, 2021;127:110670.
2019	Kluczynski MA, Kelly WH, Lashomb WM, Bisson LJ. A systematic review of the orthopaedic literature involving National Football League players. Orthop J Sports Med. August 2019;7(8):2325967119864356.
2023	Nocera A, Sbrollini A, Romagnoli S, Morettini M, Gambi E, Burattini L. Physiological and biomechanical monitoring in american Football players: a scoping review. Sensors. April 1, 2023;23(7):3538.
2015	Kent R, Forman JL, Lessley D, Crandall J. The mechanics of American football cleats on natural grass and infill-type artificial playing surfaces with loads relevant to elite athletes. Sports Biomech. 2015;14(2):246-257.
2017	Jastifer J, Kent R, Crandall J, Sherwood C, Lessley D, McCullough KA, Coughlin MJ, Anderson RB. The athletic shoe in football: apparel or protective equipment? Sports Health. March–April 2017;9(2):126-131.
2019	Wannop JW, Stefanyshyn DJ, Anderson RB, Coughlin MJ, Kent R. Development of a footwear sizing system in the National Football League. Sports Health. January–February 2019;11(1):40-46.
2019	Jastifer JR, McNitt AS, Mack CD, Kent RW, McCullough KA, Coughlin MJ, Anderson RB. Synthetic turf: history, design, maintenance, and athlete safety. Sports Health. January–February 2019;11(1):84-90.