Player position influences risk of ACL tear in the NFL

National Football League (NFL) athletes who play wide receiver or tight end may have a higher risk of suffering an injury to their anterior cruciate ligament, or ACL, according to a new study from the University of Missouri School of Medicine. 

A tear in the ACL is a significant and painful knee injury. Treatment typically requires surgery and at least 9 months of recovery, and even then, some players never return to the field.  

“An ACL tear can have major physical, mental and economic impacts to the player,” study author Clayton Nuelle said. “These are significant injuries that require prolonged rehabilitation, so it’s important to determine risk factors and identify any ways to potentially prevent future injury.” 

Wide receivers and tight ends often perform rapid change of direction movements and are involved in high-speed tackles and collisions, which likely increases the risk for ACL injury. 

“The ACL helps stabilize and prevent excessive rotation within the knee,” Nuelle said. “A tear can occur when the knee is bent awkwardly during a tackle, or during ‘non-contact’ movements, when the athlete plants and pushes off or pivots, putting the ligament under severe stress.” 

The study also examined other factors that could contribute to an ACL injury, looking at 520 tears over a ten-year period in the NFL, from the 2012-13 season to the 2022-23 season. 245 tears (47%) were caused by a contact injury mechanism, which means the player had physical contact with another person or object. A third of tears were caused by non-contact mechanisms, like landing from a jump. 

Despite past research concluding otherwise, this study did not find any significant differences in ACL tears sustained on natural grass compared to artificial turf. Turf is usually more rigid than grass, which can cause stress on the body’s joints and increase the chance of injury. This finding may be a sign of change. 

“Older studies found a higher incidence of injuries on artificial turf, when it was lower quality,” Nuelle said. “Since then, the quality, structure and composition of turf fields has improved, which may explain why this current study did not find a meaningful difference. Future research should continue to examine various injury rates, patterns and the overall safety profile.” 

The research also found that an ACL tear was more likely to happen at the beginning of the football season and during a game versus a practice, with 291 tears occurring before week 9 and only 168 tears sustained during practice, compared to 352 while in-game.

Clayton Nuelle, MD is an orthopaedic surgeon and sports medicine doctor at MU Health Care, and an associate professor of orthopaedic surgery at the Mizzou School of Medicine. He also serves as the head team doctor for Mizzou Athletics and directly takes care of the Mizzou football, soccer, swimming and diving and tennis teams.

“Anterior Cruciate Ligament Injuries in National Football League Players from 2012 to 2022: A Descriptive Epidemiology Study” was recently published in the Journal of Knee Surgery. In addition to Nuelle, Mizzou study authors include medical students Ashwin Garlapaty, Morgan Kluge and Quin Blankenship; surgical residents Rown Parola and Abdoulie Njai; James Stannard, MD, PhD, orthopaedic surgeon at MU Health Care and Medical Director of the Missouri Orthopaedic Institute; clinical research fellow Caleb Bischoff, DO; James L. Cook, DVM, PhD, OTSC, Vice Chair of Orthopaedic Research and Director of Operations & Research at the Joint and Limb Preservation Center; and Steven DeFroda, MD, orthopaedic surgeon and associate professor of orthopaedic surgery.