Monday, August 25, 2014

Does Knee Injury Impact Future Performance in NFL Players?

Several weeks ago, our post “NFL ACL Epidemic – Will This Season Be Any Different?” received a lot of activity and sparked some interesting discussions & debate on our twitter feed.  Although injuries are a part of any contact sport, if there is something you can do to prevent or reduce the incidence of are we not obligated to do that?  Looking at the number of reported non-contact ACL injuries last year in the NFL, by conservative estimates, at least 66% of those were non-contact.  Some authors and sports writers (2013: Year of Injury) put non-contact ACL injuries in the 70-75% range.  Why is that important?  Because these are the preventable injuries!
Throughout our blogs, we have highlighted the research indicating the impact on individual performance.  However, we must also consider the impact on team performance.   In one of our recent posts on twitter, we posed the question: “Does it matter to your team’s performance if your #1, #2 or #3 draft pick goes down with an ACL injury?  If it does, then prevent it.  If it does not, why are you recruiting them?”.  This is a simple question but yet one that we often don’t think about.  If you have one of your best players go down, then what does this do to your team’s seasonal performance.  If that player is your top running back, quarterback or defensive back, how does this impact your wins/loss ratio?  The impact is clear.  But what does this due to an individual player’s performance and future earning potential? 
When thinking of the individual player, this has real long term consequences both for their future performance as well as future earning potential.  According to the NFLPA the average length of an NFL player’s career is 3.3 years and according to the NFL it is 6 years.  Either way, most players will try to maximize their earnings during this time period.  Most know that knee injuries and specifically ACL injuries has a significant impact on performance and hence future earning potential.  This is why, the NFLPA rated knee injuries as the number one concern among NFL players during the 2013/14 season.  But when you look at the research to determine the impact on performance, the studies are really inconclusive.  In August 2014 issue of the American Journal of Sports Medicine, Aune et al looked at Return to Play After Partial Lateral Meniscectomy In National Football League Athletes.  In this study, 61% of the 77 NFL players undergoing partial lateral meniscectomies, were able to return to play at his previous level of competition.  The average length of time to return to play was 8.5 months.  This study also showed that the better players tended to have an increased likelihood of returning to previous level of play.  Players that were drafted in the first 4 rounds of the NFL draft were 3.7 times more likely to return and players who started more than 46.2% of the games were 2.8 times more likely to return to play.  Speed position players (running backs, receivers, linebackers and defensive backs) were 4.0 time LESS likely to return to play than non-speed position players.  Why is this? 
First, let’s look at how return to play is defined in this case.  RTP is defined, in this study, as the first time a player played in a regular season NFL game after partial lateral meniscectomy.  In the results section of this study, it is reported that although the players returned to sport, they played 25 fewer games and completed 1.8 fewer seasons than controls.  The fact that speed players were also 4.0 times less likely to return to sport than non-speed positions makes you wonder what the impact is on performance. 
In the August 2014 Journal of Orthopedics, Erickson et al published a study entitled “Performance and Return-to-Sport After ACL Reconstruction in NFL Quarterbacks”.   This study looked at 13 NFL quarterbacks who had undergone ACL reconstruction to determine rate of return to sport and performance on return to sport in comparison to controls.  This study showed that 92% of quarterbacks were able to return to sport and had an average career length post ACLR of 4.85 years.  As indicated in the table, this study also showed there was no impact on seasonal performance pre/post ACLR among these quarterbacks.  So, this would seem to indicate that there is NOT an impact on future performance.  However, if you also consider McCullough et al study published in the American Journal of Sports Medicine in 2012, they clearly showed that only 43% of players were able to return to sport at the same level of previous performance.  So, why the difference and what is the real answer?
Stay tuned next week for part II where we attempt to get more clarity on this issue.
Build Athletes to Perform…Build Athletes to Last!™

Trent Nessler, PT, MPT, DPT:  CEO/Founder ACL, LLC | Author | Innovator in Movement Science and Technology.  Dr. Nessler is a physical therapist and CEO/Founder of ACL, LLC.  He is the researcher and developer the Dynamic Movement Assessment™, Fatigue Dynamic Movement Assessment™, 3D-DMA™, author of the textbook Dynamic Movement Assessment: Enhance Performance and Prevent Injury and associate editor for the International Journal of Athletic Therapy and Training.  For more information, visit our website at  

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