Does Concussion Increase Your Risk For ACL Injury - Part III

In last week's blog, we started looking at the impact concussion has on performance and we posed the question, is there an impact on injury risk?  Logically we would say yes, but what does the research say?

In 2016, Brooks et al looked at the impact that previous history of concussion had on lower extremity musculoskeletal injuries in collegiate athletes.  In this study, the authors looked at athletes from various sports (football, soccer, hockey, volleyball, wrestling, etc) over a 3 year period from one institution.  The concussed athletes were compared to matched controls from the same sport and each were evaluated for lower extremity lower kinetic chain injuries.  What the others found was that concussed athletes were 2.48 times higher risk of lower kinetic chain injury up to 90 days after the athlete was returned to play.  However, according to this study, this became less of a risk factor as time wore on.

However, later in 2016, Gilbert et al published a paper looking at the impact that concussion had on lower extremity injuries in Division I athletes.  In this study, they looked at 335 athletes across 13 different sports and followed them for 4 years.  In literature, a P value <.05 is considered statistically significant and a strong correlation.  In this study, concussion had a strong correlation to ankle injuries (p = .012) knee injuries (p = .002) and lower extremity injuries (p = .031).


This study concluded that Division I athletes with a history of concussion are at 1.6 to 2.9 times greater risk of suffering a lower kinetic chain injury at ANY POINT throughout their Division I career.  Again, this goes right along with what we hypothesized.  That athletes with a previous history of concussion would be at greater risk of ACL injuries due to the poor performance on single limb testing.  Although this paper did not highlight concussion, it did show a high correlation to knee injuries.  According to Myers et al 2012 paper on objective return to play criteria, the authors found that single limb performance was one of the best indicators of risk in sport, especially for ACL risk. Again, considering what we learned about COM displacement, it would make sense that single limb performance would be off and hence indicate the athlete is at higher risk.

Keep in mind again, these are Division I athletes.  So based on what we know physiologically and from the research, our adolescent athletes are at even greater risk.  What does this mean?  Do we just give up and not have athletes participate in sports?  No, absolutely not.  What it tells me is:

• We need to have better preventative techniques
• We need to have better rehabilitation and return to play criteria 

Next week, we are going to look at what the research tells us about training and how we can help to reduce the potential for these kinds of injuries and what we should be including in our rehabilitation for safer return to play.  #ResearchThatWorks #ACLPlayItSafe

Dr. Nessler is a practicing physical therapist with over 20 years sports medicine clinical experience and a nationally recognized expert in the area of athletic movement assessment.  He is the developer of an athletic biomechanical analysis, is an author of a college textbook on this subject  and has performed >3000 athletic movement assessments.  He serves as the National Director of Sports Medicine Innovation for Select Medical, is Chairman of Medical Services for the International Obstacle Racing Federation and associate editor of the International Journal of Athletic Therapy and Training.