Incidence and definition
An estimated 3 million sports-related concussions occur annually in the United States. After motor vehicle accidents, sports are the second leading cause of traumatic brain injury among people age 15 to 24 years.

A concussion is defined as “a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces.” Usually, a short-lived neurologic impairment that spontaneously resolves follows a concussion. Although a concussion may result in neuropathologic (affecting the nervous system) changes, the impairment that may result after a concussion is typically functional rather than structural. Loss of consciousness (LOC) may occur, but this symptom is not determinative of whether or not a person has sustained a concussion and rarely occurs in sports-related concussions. In addition, LOC does not correlate with severity of injury.

Concussion in young athletes
Approximately 7.3 million high-school students participate in interscholastic athletics each year. About 3 million of these young athletes—around 41 percent—are adolescent girls. The number of female athletes is rising sharply; just a decade ago, only 2.4 million high-school athletes were female.

An estimated 1.6 million to 3.8 million sports-and recreation-related concussions occur every year. The leading cause of high-school sports concussion in males is football; for females, it is soccer. To date, reports of possible differences in concussion symptoms between girls and boys have been largely anecdotal. A recent study in the Journal of Athletic Training looked into these questions. The researchers surveyed certified athletic trainers at 100 high schools nationwide concerning the incidence and outcome of concussions sustained by male and female athletes during the 2005–2006 and 2006–2007 school years. They compared symptoms, symptom resolution time, and time to return to play between males and females with sports-related concussions.

For each high-school student who sustained a concussion, trainers were asked to respond to a questionnaire using an Internet-based injury reporting system. Respondents reported how long it took the symptoms to resolve and how long it took the athlete to return to play. A total of 812 concussions were assessed—610 in boys and 202 in girls—over the 2-year study.

Headache was the primary symptom reported for athletes of both sexes in both years of the study. Although no difference in incidence of headache was revealed, other primary symptoms did differ by sex. Amnesia and confusion/disorientation (ie, cognitive symptoms) were reported as primary symptoms for males more frequently than for females, and the difference was statistically significant.

During the second year of the study, trainers were asked to report all symptoms, not just the primary symptom. No substantial difference was found in the median number of symptoms reported for girls or boys. Amnesia and confusion/disorientation were reported more frequently for boys than for girls to a statistically significant extent; however, drowsiness (a neurobehavioral symptom) and sensitivity to noise (a somatic symptom) were reported significantly more frequently for girls than for boys. No differences were observed between sexes for symptom resolution time or return-to-play time.

Assessing concussion
Normative data are useful in assessing concussion, but little normative data exists for high-school athletes. Previous studies on college athletes have shown that, in general, female athletes score better on tests of neurocognitive function. Female collegiate athletes were also shown to perform significantly better than male athletes on baseline verbal memory scores, while male athletes performed significantly better than female athletes on baseline visual memory scores. Female athletes also reported a significant number of mild baseline symptoms as compared to male athletes.

One way clinicians assess concussions is to use a neurocognitive tool. The Sports Concussion Assessment Tool (SCAT) is a paper neurocognitive tool that was developed in 2005 after the Second International Conference on Concussion in Sport, held in Prague in 2004. SCAT combined several existing tools and was developed for patient assessment and physician evaluation in those athletes who sustained a sports-related concussion. It contains both subjective and evaluation portions.

A study of SCAT normative (baseline) data from male and female youth hockey found that ratings varied between age groups and genders; they also varied from previous reports on varsity athletes.

Based on symptom-resolution and return-to-play time, little difference is evident in the severity or outcome of concussions sustained by high-school athletes of either sex. But recent findings indicate that adolescent male and female athletes may have different types of symptoms after a sports-related concussion and that these symptoms may be interpreted differently by healthcare professionals. Without adequate assessment, the neurobehavioral or somatic symptoms reported by girls may be more easily missed or even attributed to other conditions such as stress or anxiety.

Symptom evaluation is only one component of a concussion evaluation, and each symptom should be evaluated and monitored to resolution before the athlete can return to play. Neurocognitive assessments, balance measurements, symptoms, and the physical examination should be used collectively to evaluate concussions.

Elizabeth Arendt, MD, is a professor at the University of Minnesota and chair of the AAOS Women’s Health Issues Advisory Board. Margot Putukian, MD, FACSM, is director of athletic medicine at Princeton University.

Putting sex in your orthopaedic practice
This quarterly column from the AAOS Women’s Health Issues Advisory Board and the Ruth Jackson Orthopaedic Society provides important information for your practice about issues related to sex (determined by our chromosomes) and gender (how we present ourselves as male or female, which can be influenced by environment, families and peers, and social institutions). It’s our mission to promote the philosophy that male and female patients experience and react to musculoskeletal conditions differently; when it comes to patient care, surgeons should not have a one-size-fits-all mentality.

Online references:

1. Buzzini SR, Guskiewicz KM: Sport-related concussion in the young athlete. Curr Opin Pediatr 2006;18(4):376.
2. Gessel LM, Fields SK, Collins CL, Dick RW, Comstock RD: Concussions among United States high school and collegiate athletes. J Athl Train 2007;42(4):495-503.
3. McCrory P, Johnston K, Meeuwisse W, et al: Summary and agreement statement of the 2nd International Conference on Concussion in Sport, Prague 2004. Br J Sports Med 2005;39(4):196-204.
4. Lovell M, Collins M, Bradley J. Return to play following sports-related concussion. Clin Sports Med 2004;23(3):421–441.
5. Frommer LF, Gurka KK, Cross KM, Ingersoll CD, Comstock RD, Saliba SA: Sex differences in concussion symptoms of high school athletes. J Athl Train 2011;46(1):76-84.
6. Shehata N, Wiley JP, Richea S, Benson BW, Duits L, Meeuwisse WH: Sport concussion assessment tool: Baseline values for varsity collision sport athletes. Br J Sports Med 2009;43(10):730–734.
7. Covassin T, Swanik CB, Sachs M, et al: Sex differences in baseline neuropsychological function and concussion symptoms of collegiate athletes. Br J Sports Med 2006;40(11):923–927.