“Advanced helmet technology has not affected the concussion rate or the rate of intracranial injury among high school and college football players,” said John R. Fowler, MD, a PGY-5 resident at Temple Orthopaedics & Sports Medicine in Philadelphia. “Our data suggest that we need further research to determine the predisposing profiles for mild traumatic brain injury (MTBI), postconcussion syndrome, catastrophic brain injury, and chronic sequelae.”

Dr. Fowler presented his paper, “Helmet Characteristics as Profile Elements Identifying Susceptibility to Mild Traumatic Brain Injury (Concussion) in Tackle Football” during the 2012 American Orthopaedic Society for Sports Medicine Specialty Day meeting. The research team examined reports on 1,398 concussions collected through the National High School Sports-Related Injury Surveillance System, using loss of consciousness (LOC) and amnesia as hard end points to determine concussion severity. They took into account various helmet designs to determine if particular helmets were more likely to be associated with injury.

Concussion rates steady
“We found that athletes wearing properly fitted helmets, as determined by the athletic trainer, were 82 percent less likely to experience LOC in association with their concussion,” he said. “The bladder lining—whether foam, air, or gel—had no significant effect on the incidence of amnesia or LOC. Helmet age and condition, whether new or reconditioned, were also not predictors of amnesia or LOC in association with the concussion.”

Dr. Fowler cited data from previous studies that, taken together, suggest that advances in helmet technology have had little effect on the number of concussions among high school and college players.

“There’s been a constant rate of MTBI in high school football players over the last 30 years,” he explained, “with an average participating number of 1.1 million players per year. This suggests a strong profile commonality of specific values that predispose to concussion and postconcussion syndrome.”

Dr. Fowler pointed to another study that looked at catastrophic intracranial injuries such as subdural hematoma over a 20-year span. Similar to the data on concussion, that study found a constant rate of catastrophic intracranial injury in both high school and college football players, again suggesting a profile commonality of specific factors that predispose to catastrophic intracranial injury.

However, preliminary data from another, yet unpublished study by the same lead author, showed increased risk of catastrophic brain injury among players using air bladder helmets.

“Overall, 84 percent of the players who had subdural hematomas in that series were wearing air bladder-lined helmets when they had their injury,” said Dr. Fowler.

More data needed
Dr. Fowler reviewed the variety of factors that have been suggested as potential components of the susceptibility profile, including the following:

• environmental and metabolic factors
• medications
• illness
• depression
• ambient temperature

According to Dr. Fowler, current research has fallen short of identifying the components, making it impossible to implement broad changes to minimize risk.

“In our opinion, the first—and currently unappreciated—step in resolving the acute brain injury problems is to identify the components of the susceptibility profile,” he said. “Then, we can implement changes to disrupt the predisposing injury combinations.

“Current data show that poor helmet fit and air bladder lining are associated with both concussion and catastrophic intracranial events. It’s the responsibility of the athletic director and head football coach to ensure that each player has a properly fitted helmet. In addition, we suggest that a responsible adult verify on a weekly basis that helmet air bladders are properly inflated.”

Dr. Fowler’s coauthors on the study include Joseph S. Torg, MD; Hank Hirsch, MS, ATC; Barry P. Boden, MD; R. Dawn Comstock, PhD; and John P. Gaughan, PhD. All of the authors reported no conflicts of interest.

Peter Pollack is a staff writer for AAOS Now. He can be reached at ppollack@aaos.org

Bottom Line

• Despite advancement in helmet technology, the rates of concussion and intracranial injury among high school and college football players have remained unchanged.
• Wearing a properly fitted helmets, as determined by the athletic trainer, can reduce the likelihood that an athlete will experience loss of consciousness in association with a concussion.
• Current research has fallen short of identifying potential components of a susceptibility profile, making it impossible to implement broad changes to minimize risk.

References

1. Selected Issues in Injury and Illness Prevention and the Team Physician: A Consensus Statement
2. Ringing the bell on concussion management
3. Sex-related differences in concussion symptoms
4. Concussion Incidence in Elite College Soccer Players
5. Helmet Characteristics as Profile Elements Identifying Susceptibility to Mild Traumatic Brain Injury (Concussion) in Tackle Football (AOSSM members only)