Unintended Consequences of Concussion Prevention in NCAA Football

OBJECTIVES: Both lower extremity and head injuries are common in American Football players. Concussions, or Mild Traumatic Brain Injuries (MTBIs), have gained increased interest in the past decade. Recurrent MTBIs have been associated with late-life cognitive impairment and depression in American Football populations.2, 3 Beginning in 2008, the NCAA introduced rule changes with the intent to halt or reverse the increasing rates of MTBIs in its players. Lower-extremity injuries in American football populations have been associated with increased rates of post-traumatic osteoarthritis1 and significantly contribute to disability in retirement. While lower extremity injury rates have been studied and associated with weather5 and playing surface4, no such study has sought an association between lower extremity injury with the timing/introduction of rule changes used to prevent head injuries. The purpose of this study was to assess if lower extremity injury rates are increasing after concussion rule changes. We hypothesize that there may be a compensatory increase in lower extremity injury rates as players act to avoid head-to-head contact and comply with instated rules. METHODS: The NCAA Injury Surveillance System (NCAA ISS) database was queried for in-game injuries suffered between 2009-2014. All injuries suffered by NCAA Football players that occurred in competition were identified. Injuries that did not result in lost participation time were excluded. Lower extremity injuries that resulted in lost time included injuries to the thigh/upper leg, knee, lower leg/Achilles, ankle and foot. All concussions resulting in lost time were also identified during the same time period for comparison. Data regarding athletic exposures was collected in order to calculate the incidence of injury. RESULTS: Between 2009 and 2014, 48 NCAA Football programs provided data on123 team-seasons to the NCAA ISS for analysis. The incidence of lower extremity injuries increased from 9.45 injuries per 1000AE in the 2009-2010 season to 12.63 injuries per 1000AE in the 2013-2014 season. The rate of concussions suffered by American Football players, during the same time period, did not significantly change (1.64 concussions per 1000AE’s in 2009-2010 season versus 2.87 concussions per 1000 AE’s in the 2013-2014 season) [Graph 1]. CONCLUSION: Given heightened societal interest in concussions, the NCAA has implemented several rule changes in order to influence how American Football is played. Since the initiation of these rule changes, concussion rates have remained stable. During our study period, injuries to the lower extremity have increased. In order to comply with avoiding head-to-head contact, players may be targeting the lower extremities. This is concerning as lower extremity injuries and post-traumatic osteoarthritis are common causes of disability in retired American Football players.