Sex-Based Differences in Common Sports Injuries

Cordelia W. Carter, MD; Mary Lloyd Ireland, MD; Anthony E. Johnson, MD; William N. Levine, MD; Scott Martin, MD; Asheesh Bedi, MD; Elizabeth G. Matzkin, MD


J Am Acad Orthop Surg. 2018;26(13):447-454. 

In This Article

Stress Fracture

Since the implementation of Title IX in 1972, the number of females participating in sports has increased dramatically at all levels of play. Thus, the number of SRIs has also increased. One injury that first seemed to be particularly common in this population was stress fracture, often seen in the context of hormonal and dietary irregularities. When the Task Force on Women's Issues of the American College of Sports Medicine was assembled in 1992, the term "Female Athlete Triad (FAT)" was created to describe the interrelated pathologies of disordered eating, amenorrhea, and low bone mineral density (BMD); all three components had to be present simultaneously for a diagnosis of FAT.

In 2007, the American College of Sports Medicine updated the diagnostic guidelines, and FAT was redefined to include a constellation of abnormalities including those related to energy availability (EA), menstrual function, and BMD.[5] Each component is part of a spectrum ranging from normal to increasing degrees of pathology. The female athlete no longer must demonstrate pathology in all three components of the triad to be diagnosed with the syndrome.

Determining the true prevalence of FAT is difficult, especially as the definition continues to evolve. Studies have demonstrated low EA in up to 36% of female high school athletes,[6] 63% of endurance athletes,[7] and 77% in ballet dancers.[8] The same group of authors identified menstrual dysfunction in 54% of high school athletes, 60% of endurance athletes, and 36% of ballet dancers. In a study of female endurance athletes, Melin et al[7] reported that 45% had impaired bone health and 25% demonstrated all three components of the triad.

In 2014, Barrack et al[9] reported that 11% of adolescent female athletes in their study population had a bone stress injury secondary to FAT. This finding is particularly concerning because 90% of peak bone mass is accrued by adolescence; a normal adolescent female gains approximately 2% bone mass per year, whereas an amenorrheic female loses 2% per year. If young female athletes fail to maximize their bone mass during the normal period of accrual, they may have an increased risk for osteoporosis and associated fragility fractures later in life.[10] The most common musculoskeletal manifestation of the FAT is stress fracture, and females are at a greater risk of this complication. In a 2011 systematic review of the incidence of stress fracture in military and athletic populations, Wentz et al[11] reported stress fractures in 9.7% of female athletes compared with 6.5% in male athletes. In the military population, females fared worse than males, with a reported stress fracture incidence of more than three times that of males.

Acknowledging that athletes of both sexes might be at risk for impaired bone health resulting from nutritional and neuroendocrine abnormalities, the International Olympic Committee convened in 2014 and published a consensus statement titled, "Beyond the FAT—Relative Energy Deficiency in Sport (RED-S)."[12] The term "RED-S" is intended to be a broader and more comprehensive definition of pathology secondary to a relative energy deficiency that may occur in any athlete, irrespective of sex.[12]

Highlighting the fact that RED-S may affect both male and female athletes, Tenforde et al[13] examined components of this syndrome in male athletes. These authors noted that male athletes, like their female counterparts, may sustain bone stress injuries in the setting of nutritional and endocrine abnormalities. They suggested that hypogonadotropic hypogonadism (characterized in males by low serum testosterone levels with concomitant clinical symptoms, such as low BMD, reduced energy and stamina, oligospermia, and decreased libido) is analogous to the hypothalamic amenorrhea component of FAT. Tenforde et al[13] proposed that a subset of male athletes may present with a combination of low EA, hypogonadotropic hypogonadism, and low BMD, in which each component exists on a spectrum similar to that characterizing FAT.[13] In addition, just as has been reported for female athletes, male athletes who seem to be most at risk for developing RED-S commonly participate in sports emphasizing leanness, including aesthetic sports (eg, gymnastics), endurance sports (eg, running, cycling), and sports with a weight classification (eg, rowing, wrestling).[10,14]

A recent study on awareness of FAT among multispecialty physicians demonstrated that only 37% of physicians across disciplines had heard of the triad.[15] This highlights the importance of continued education for all athletes, coaches, and physicians about RED-S, including its signs, symptoms, and at-risk populations (both female and male), so that the potential negative consequences of RED-S on long-term reproductive and skeletal health can be mitigated.