Sex-Related Differences in Hip Injury Rates and Strength and Conditioning





Hip injuries are common in the athletic population, typically occurring in sports as a result of contact or overuse. Previous literature describes differences in injury rates between male and female athletes, clinical presentation, treatment, and outcomes. In addition, anatomic differences in acetabular and femoral version, hip alpha angles, lateral center-edge angles, pelvic tilt, and knee biomechanics have been demonstrated. These differences may alter injury patterns between male and female athletes and contribute to differences in hip pathology. Therefore, individualized treatment and rehabilitation strategies should be taken into consideration in order to expedite an athlete’s return to play.


Key points








  • Although hip-related injuries are common in both the male and female populations, differences in anatomy, hip abductor strength and function, and landing biomechanics have been demonstrated within the literature.



  • These differences can affect injury pattern, incidence, and outcomes.



  • Both male and female athletes of all age groups benefit from injury prevention programs.



  • Structured strength and conditioning programs are pivotal in developing an athlete’s body both for on-field performance and to help prevent injury.




Introduction


Hip injuries are common in the athletic population, with a reported rate of approximately 1 per 2000 athletic exposures. , Of all collegiate sports, men’s soccer (110.84 per 100,000 athletic exposures) and men’s and women’s ice hockey (104.9 and 76.88 per 100,000 athletic exposures, respectively) had the highest rates of hip injury. Although previous epidemiologic studies have demonstrated that female athletes have a higher rate of hip injury in college athletics in sex-comparable sports, more recent studies dispute this by showing a higher rate of hip injury in male athletes both within the National Collegiate Athletic Association (NCAA) and in international athletic competition. Hip injuries occur most commonly in sports that require impingement-type movements and can be a result of either contact or overuse. Higher rates of overuse hip injuries have been reported in female athletes compared with contact-related injuries in their male counterparts. , Although more than one-third of hip injuries in the NCAA led to time lost from competition, only approximately 1 in 100 injuries required surgery. Therefore, in order to effectively diagnose and treat hip injuries in athletes, the differences in injury rates between male and female athletes, clinical presentation, treatment, and outcomes should be taken into consideration in order to expedite an athlete’s return to play.


Sex-related differences in hip anatomy and biomechanics


Although hip-related injuries are common in both male and female athletes, differences in anatomy, hip abductor strength and function, and landing biomechanics have been demonstrated within the literature ( Table 1 ). These differences can affect injury pattern, incidence, and outcomes. Anatomic-based differences have been described previously, with studies reporting that women have increased acetabular version, increased femoral anteversion, smaller alpha angles, and a decreased lateral center-edge angle. Nguyen and colleagues reported that women have greater anterior pelvic tilt, femoral internal rotation, knee hyperextension, and knee valgus compared with men. These described differences all may contribute to variations in injury patterns affecting male and female patients. Erector spinae and hip flexor tightness combined with abdominal and gluteal weakness has been found to contribute to greater anterior pelvic angles, which supports the findings that women tend to have decreased strength during hip range of motion as well as an increase in lumbar lordosis compared with men.



Table 1

Sex-related anatomic and kinematic differences








































Parameter Male Female
Acetabular version 17.8° ± 6.5° 21.3° ± 7.6°
Acetabular inclination 36° ± 3.6° 38.5° ± 4.5°
Femoral head diameter 48.6 mm ± 2.3 mm 43 mm ± 2.4 mm
Femoral anteversion 19.4° ± 10.4° 23.9° ± 9.8°
Alpha angle 47.8° 63.6°
Lateral center-edge angle 37.9° ± 5.3° 34.7° ± 6.1°
Hip abductor torque 7.2% ± 1.5% 5.8% ± 1.2%
Knee valgus joint displacement 7.26° ± 6.61° 3.29° ± 3.54°


Differences in abductor function and landing kinematics between men and women have also been demonstrated in the literature. Jacobs and colleagues assessed landing kinematics of hopping from 2 legs onto 1 leg in 15 men (24.4 years ± 3 years) and 15 women (23.2 years ± 2.9 years). They evaluated for differences in peak torque, endurance capacity, and peak joint displacement and demonstrated that women have lower hip abductor peak torque values, increased knee valgus peak joint displacement, and a larger correlation between hip abductor strength and landing kinematics compared with their male counterparts (see Table 1 ). In addition, the investigators report a small positive correlation between strength and kinematics in men and a large negative correlation in women. These differences suggest that hip abductor strength and lower extremity kinematics likely are dissimilar between men and women, with hip mechanics in women offering more protection around the hip joint during landing activities. Previous studies also have demonstrated that female athletes have a lower peak hip abduction torque related to body mass compared with their male counterparts. Brent and colleagues conducted a biomechanical study evaluating the standing isokinetic hip-abduction torque in 79 male (13.65 years ± 1.6 years) and 272 female (14 years ± 2.2 years) adolescent soccer and basketball players using a dynamometer. They demonstrated that not only did male players have increased peak torque values compared with female players, but also they had greater increases in peak torque relative to body weight than did female players as they matured. Therefore, hip-abductor strengthening exercises should be performed, especially in female athletes, as part of preventative and rehabilitative strengthening programs.


Sex-related differences in hip pathology


A majority of injuries sustained during athletic competition typically are muscular in origin, comprising approximately 40% of all injuries. Hamstring strains affect male athletes more commonly than female athletes in athletic competition. When considering gender differences in hamstring injuries among all age groups, female athletes tend to be older and sustain injuries during everyday activities, whereas male athletes are younger and injured more commonly while playing sports. Thigh muscle strains also are a common muscular injury, affecting both male and female athletes. Gender difference data are conflicting for these injuries. In high school soccer, thigh muscle strains were shown to occur more commonly in female athletes than in male athletes, with male athletes having a rate ratio of 0.66. But, in adult international competition, thigh muscle strains occurred more often in male athletes, with an incidence of 52 per 1000 athletes compared with women, who had an incidence of 30 per 1000 athletes. More research is required to determine whether gender differences in muscle injury truly are significant. Eckard and colleagues evaluated hip flexor and adductor strains in collegiate athletes in 25 different NCAA sports and demonstrated that female collegiate athletes had higher rates of hip adductor muscle strains compared with male athletes in comparable sports, with an incidence rate ratio of 1.49, but the rates of hip flexor injury did not show significant statistical difference, at a rate ratio of 1.14. Regardless of potential differences between genders, it is clear that muscle injuries about the hip are common and should be included in the differential when evaluating an injured athlete.


A common cause of pain in athletes may be due to femoroacetabular impingement (FAI), and the sequelae created by this mechanical abnormality can cause significant disability and limit athletic performance. When treating athletes with this condition, gender may play a significant role in diagnosis, treatment, and eventual outcome. The clinical presentation of male athletes and female athletes with FAI is similar, with most patients having an insidious onset of groin pain made worse by activity, decreased hip range of motion, and a positive impingement test on physical examination. In cadaver analysis, female acetabula demonstrate increased anteversion compared with male acetabula. Increased anteversion can create over-coverage of the femoral head leading to pincer-type FAI. Therefore, female athletes may be expected to present with pincer-type FAIs more often than male athletes. Hooper and colleagues conducted a retrospective review examining 177 adolescent patients aged 13 years to 18 years who underwent hip arthroscopy for treatment of FAI. They demonstrated that male patients had a smaller preoperative lateral center-edge angle than female patients. This supports the idea that female athletes are more likely to have pincer-type FAI because the lateral center-edge angle is a measure of coverage of the femoral head by the acetabulum. Previous studies have demonstrated that male athletes have a higher alpha angle, which is a measurement used to evaluate for a cam deformity, as well as increased chondral damage assessed intraoperatively. This supports the concept that male athletes are more likely than female athletes to have cam-type FAI, which can lead to increased rates of chondral damage.


Hip arthroscopy is a common treatment of FAI and an extended recovery time can be expected after such a procedure. Among male patients, athletes have been shown to recover faster from hip arthroscopy than nonathletes. In addition, high-level athletes who receive arthroscopic treatment of FAI are more likely to be male and younger, play a cutting sport, and have bilateral surgery compared with recreational athletes. Therefore, participation in high-level athletics might cause clinical symptoms stemming from underlying structural abnormalities within the hip at an earlier age, especially in sports that require significant amounts of cutting. Joseph and colleagues evaluated 156 female athletes and 73 male athletes with an average age of 31, who underwent arthroscopic treatment of FAI, and demonstrated that although female athletes had poorer preoperative function, both male and female patients reported continual functional improvement within their hip until 6 months postoperatively. The same study showed no significant differences between male athletes and female athletes in hip function 2 years after surgery.


Lastly, femoral neck stress fractures are a commonly reported injury within the athletic population and can be a major cause of disability. Studies have demonstrated higher rates of femoral neck stress fractures within the female international athletic population compared with their male counterparts. Stress fractures around the hip are less common than other stress fractures in athletes with femoral neck stress fractures, accounting for only 3% of all sports-related stress fractures. Femoral neck stress fractures are reported most commonly in sports involving long distance running; therefore, clinicians must have a high index of suspicion because early diagnosis has been shown to lead to improved outcomes. Reinking and colleagues examined 64 female and 20 male collegiate athletes in several sports for lower extremity overuse bone injuries and found no association between risk of injury and gender. The investigators demonstrated that cross-country and track athletes are more likely to sustain these injuries than participants in other sports, with a relative risk of 2.26. They also found that athletes with lower bone mineral density within the calcaneus had a relative risk for developing an overuse injury of 2.1 compared with athletes with normal bone mineral density.


Within the current literature, gender differences in hip pathology have become increasingly recognized. Muscle injuries, FAI, and stress fractures are common injuries affecting both male and female athletes and understanding the differences between the sexes in their incidence, diagnosis, treatment, and outcomes is important in order to manage and treat patients more effectively ( Table 2 ). Overall, more research is required to advance understanding of these topics in order to improve the care of both male and female athletic injuries.


Jun 13, 2021 | Posted by in SPORT MEDICINE | Comments Off on Sex-Related Differences in Hip Injury Rates and Strength and Conditioning

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