Anterior Cruciate Ligament Injury - Female Susceptibility

Female Susceptibility

Since the Title IX enactment that made it illegal to discriminate in the education system based on gender in the USA, the percentage of female athletes has risen considerably. By 1998, the percentage of girls participating in high school level sports was ten times the amount that had participated in the previous decade, rising from 3.7% in 1971 to 33% in 1998. With female participation in high-level competition sports on the rise, doctors were finding more and more instances of anterior cruciate ligament (ACL) injuries. According to ACL Tears in Female Athletes, seventy percent of ACL related injuries occur during athletic competition. Of this seventy percent, a majority of ACL tears occur during sports that require quick stopping, cutting, and rapid changes of direction—sports like soccer, basketball and lacrosse. When the National Collegiate Athletic Association (NCAA) compared statistics from these high-risk sports where male and female athletes have similar equipment and rules, they found that ACL injuries occurred two to eight times more likely in females than in males. Doctors have studied a combination of environmental, hormonal, neuromuscular and biomechanical factors that make the female athlete more prone to ACL tears and have used this information to determine ways to prevent future injury. There are many environmental factors that come in to play with female athletes. The first deals with the friction between shoes and surface type. Surfaces that increase friction between player and field of activity can alter the movements of athletes and increase their risk of injury. One such example is drier surface. They increase the friction between shoe and surface therefore increasing risk of ACL injury, whereas wet surfaces have the opposite effect. Doctors still remain controversial over whether artificial turf increases or decreases risk of tears although there has been evidence to support both. The type of shoe, as mentioned earlier also plays a role. Cleat size and shape specifically seems to trigger injury where fewer injuries have been correlated to smaller and fewer cleats. The other environmental factor is knee bracing. Although many females chose to wear a brace on their knee to prevent injury, their actual effect on preventing injury remains controversial. Prophylactic, functional, and postoperative are all types of braces that have been used to prevent ACL injuries or reinjuries. Prophylactic bracing has been shown to improve the knee’s resistance to lateral movement twenty to thirty percent in a controlled experimental setting. On the contrary, a study done by Houston and Goemans found that braced collegiate athletes have a higher incidence of ACL tears that those athletes who don’t wear one. There is also research that suggests no difference in strength, laxity or function in the braced and non-braced knee, however most studies support that wearing a brace does not reduce injury to the knee or ACL.

There are various internal factors that play a role in the increased amount of ACL injuries found in females. Female body structures as well as certain hormones are the leading contributors to this epidemic. Females have a wider pelvis, shorter femurs, and less developed thigh muscles than males, which can cause stress from impact and movement to lie on specific ligaments or tissues rather than on the muscles themselves. “These differences form a more lateral proximal reference point, increase lateral pull of the quadriceps muscle on the patella and put medial stress on the knee” Women have larger quadriceps angles than men which determine the force the quads put on the patella during leg extension. When this angle is larger, the quadriceps have a greater pull on the patella, causing increased stress on the knee. Women lack the same neuromuscular spurt that males undergo during puberty. This spurt directly correlates with an individual’s strength and coordination, and these muscles are what stabilize the knee and protect it. Without this, women’s bodies bear more of the stress of physical activity on their joints rather than on their muscles. The hyperextension of the knee means that the ACL is more likely to tear. According to Dr. C. David Geier, an orthopedic surgeon and director of the Medical University of South Carolina Sports Medicine program, there is a difference in neuromuscular patterns and activities in females compared to males. Female athletes are more likely to land and turn with their knees straight compared to males who tend to do so with bent knees. ACL injuries have also been reported to be more common during menstruation. Certain female hormones can affect bone, muscle, and tissue in the body. During menstruation, estrogen receptors near the ACL may cause it to become more relaxed, which increases its likeliness for injury. The hormone relaxin, found in females during pregnancy, is also related to the loosening of this ligament.

Most anterior cruciate ligament, or ACL, injuries are due to non-contact events. This means that prevention techniques are an important possibility for active people. Though there are many prevention techniques for ACL injuries many are not gender specific. Some of the key factors when talking about injury prevention include training, flexibility, and knowledge. Probably the most important factor in prevention would be the training aspect. Researchers suggest neuromuscular training to help greatly reduce the chance of ACL injury. Many women compared to men have insufficient training, which could explain the increased amount of ACL injuries. In this training, strength should play an important role. Strengthening the surrounding muscles of the ACL can help in preventing an injury. These muscles in particular include the quads and hamstrings. In general women have weaker legs including the important muscles located around the ACL. Studies have shown that women rely too much on quad strength and less on hamstring strength when these muscles should be used almost equally. This poses a problem because increased quad muscles in addition to the decreased knee and hip flexion and valgus knee angles and movements is the reason for the greater number of ACL tears in women over men. In addition, the decrease in hip extension causes women to compensate by landing with a stiff knee. This is very dangerous to the ACL. Overall, neuromuscular training is an effective prevention technique for ACL injuries however timing also plays a big role in this method. Gregory Myer, a researcher at Cincinnati Children’s Hospital in Ohio, conducted a study that proved the earlier females start this neuromuscular training the more effective it will be. Myer found that females who had been introduced to neuromuscular training before age fourteen were 72% less likely to hurt the ligaments in their knee. This is compared to women who started preventative training at twenty had the same risk as women who did not participate in the training. Another important aspect in prevention of ACL injuries is knowledge. Studies have shown that many injuries are due to awkward movements or positions while participating in sport. These can be reduced though knowledge of what can or cannot be harmful to the ACL. There are numerous programs that not only build up strength in the knee and leg but also inform the participants about causes and preventions of this injury. One major example of this would be that women are more prone to partaking in rapid deceleration. This is detrimental to the anterior cruciate ligament however some women may not know this fact. With these programs and other forms of education women would be informed about this and be able to stop decelerating rapidly and learn to gradually slow down. Although no prevention technique can guarantee the absence of ACL injuries, women should partake in early, active and smart training to strengthen and prevent problems with the anterior cruciate ligament.