Sports Medicine Research: In the Lab & In the Field: Increased Risk of Acute Lower Extremity Injury For Up To a Year Following Concussion (Sports Med Res)
Tuesday, July 21, 2015

Increased Risk of Acute Lower Extremity Injury For Up To a Year Following Concussion

Acute Lower Extremity Injury Rates Increase following Concussion in College Athletes

Lynall RC, Mauntel TC, Padua DA, Mihalik JP. Med Sci Sport Exerc. 2015; ahead of print

Take Home Message: College athletes are nearly 2 times more likely to sustain an acute lower extremity injury for up to 1-year post concussion compared with a year before the concussion.

Neuromuscular control deficits change functional movement patterns during simple gait activities (for example, increase sway area) following a concussion. These changes continue well beyond the athlete’s full return-to-play, which is worrisome because these lingering changes may put the athlete at risk for a lower extremity injury. However, there is limited research addressing the risk of lower extremity injury following a concussion. Therefore, the authors investigated the risk of lower extremity musculoskeletal injury pre and post concussion in a cohort of 44 Division I athletes within 3 time periods around a concussion injury (± 90, ± 180, and ± 360 days). The authors also compared concussed athletes with 58 healthy matched controls. The concussion group had no previous history of concussion before the concussion that was evaluated in this study. The control group was matched for sex, sport, competition playing time, age, height, and weight. Musculoskeletal injury and concussion data were collected from the institution’s electronic medical record system. Information about all injuries and illnesses were recorded for 365 days prior to the concussion of interest and 365 days after return-to-play. Lower extremity musculoskeletal data (for example, type of injury, location of injury, mechanism of injury, days out of sport activity due to injury, and days of limited athletic participation due to injury) were collected for the matched controls for the same time periods as their matched concussed participant. Athletic-exposure rates for each athlete were calculated based on the number of days of physical activity while on a team. There were no differences between groups in regards to age, height, or weight. An athlete in the concussion group was almost twice as likely to experience an acute lower musculoskeletal injury following a concussion than during a similar time interval before the concussion. In contrast, there were no differences over time in lower extremity musculoskeletal injury rates within control group. There were also no differences in injury rates between the concussed and control groups prior to concussion; however, the concussed group was 65% more likely to have an acute lower extremity injury compared with the control group for a year after a concussion.

The authors demonstrated that college athletes are almost twice as likely to suffer acute lower extremity injury following a concussion. Additionally, it is alarming to see that these athletes were at risk for an injury up to 180 and 365-days post injury, which brings up more questions such as “Are we doing enough to rehabilitate a concussed athlete before returning them to play?” It is important to note that the concussed athletes only had a greater risk of injury after the concussion and not when compared with the control group prior to a concussion. Therefore, it is unlikely that the greater risk of injury is related to an athlete’s aggressiveness or risk taking on the field. Instead this increased risk could be attributed to neuromuscular control deficits, which could change functional movement patterns, and increase an athlete’s risk of lower extremity injury. However, this study did not directly investigate possible mechanisms for the increased musculoskeletal rates so more research needs to be done to validate of these findings. Still, the concussed group may be susceptible to an injury. Therefore, medical professionals should be aware of possible neuromuscular deficits that could impair athletic abilities, which can put their athletes at risk for lower extremity musculoskeletal injuries. Additionally, we may want to consider implementing functional movement pattern assessments and rehabilitation before returning an athlete to play even though this may warrant more research.

Questions for Discussion:  Do you include any functional movement pattern in your concussion assessment protocol to determine readiness to return to play after injury? Should there be a functional movement rehabilitation following a concussion to potentially decrease risk of lower extremity injuries? Do you think acute upper extremity injury rates post concussion would also be affected?

Written by: Jane McDevitt, PhD
Reviewed by: Jeff Driban

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Lynall RC, Mauntel TC, Padua DA, & Mihalik JP (2015). Acute Lower Extremity Injury Rates Increase following Concussion in College Athletes. Medicine and Science in Sports and Exercise PMID: 26057941

2 comments:

Shelby M. said...

While I do not clinically use functional movement assessments as a tool for return to play decisions, I think it is something to consider implementing. In my previous clinical setting the return to play protocol focused primarily on cardio, but did allow athletes to compete in non-contact drills on the fourth day. The protocol never fully focused on functional movement patterns but the athlete briefly participated in agility drills and sport specific movement drills. The athlete was introduced into functional sport specific movements but balance and proprioception are never focused on in return to play post concussion. There is a greater focus on the athlete staying asymptomatic.
It was easy to assume the balance decreases that would result from a concussion could result in increased injury rates; however, without fully understanding the causes of the increase in injury occurrences, I feel it would be difficult to gain support including functional movement in a return to play protocol. I also question how would one determine a baseline for functional movement. Often times collegiate athletes arrive their freshman year and complete their baseline Impact and BESS. Once a student has completed this, their next four to five years are based on something they took as a freshman. Skill levels can change drastically over the first semester of practice, making the baseline for functional movement flawed. I am interested to hear on how one would implement and assess functional movement for an athlete, as well as, what would serve as a baseline for the athlete, if any baseline at all.
I do not think that upper extremity injuries would increase post concussion simply because, the researchers hypothesized that the increase came from disrupted cortical pathways, decreasing reaction and movement times. Which in essence the balance and proprioception deficits observed post concussion should not have as great of effect on upper extremity injury occurrences. I would be interested to see a study on upper extremity injury occurrences post concussion still.

Jane McDevitt said...

Shelby,
I agree that there are many variables to consider with a functional movement screen. First and mostly importantly what is the protocol. Also, it seems that it would be necessary to baseline test, and that especially at a collegiate level you would need to baseline test every year.

I am not sure an upper extremity injury would would increase risk of concussion. If so, I would be surprised if an athlete would be 2 times more likely to sustain a concussion like the authors in this study demonstrated for a lower extremity injury; however, like you said I would still read it.

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