By Dr. Mark Cullen, Wentworth Health Partners Seacoast Orthopedics & Sports Medicine 

Soccer is widely regarded as the most popular sport globally in terms of both audience and participation. Since the passage of Title IX in 1972, the number of females participating in sports in high school has increased tenfold. Over 3 million girls now participate in high school sports each year. There are over 3 million youth soccer participants in the United States. New Hampshire has 19,000 youth soccer players. The success of the United States Women’s National Team has led to the tremendous growth of women’s soccer in The United States.

Unfortunately, most female soccer players know someone who has experienced an ACL injury.

Female athletes have a 4-6x increased risk of ACL injuries than males in cutting sports.

Unfortunately, most female soccer players know someone who has experienced an ACL injury. The risk of ACL injury is unusually high in women’s soccer. Female athletes have a 4-6x increased risk of ACL injuries than males in cutting sports, and overall, girls are eight times more likely to suffer an ACL injury than boys. In the United States, as many as 80,000 high school female athletes experience ACL injuries each year, with most ACL tears occurring in soccer and basketball. The incidence of ACL tears in females’ peaks at the age of 16.

Year-round female athletes who play soccer or basketball have a 5% chance of tearing their ACL each year they participate in their sport.

If an athlete returns to playing soccer, there is a high risk of further ACL injury (30%) to either the operative or nonoperative knee.

Year-round female athletes who play soccer or basketball have a 5% chance of tearing their ACL each year they participate in their sport. That represents a 20% chance of tearing your ACL while participating in high school soccer. Athletes and their families need to be counseled that less than half of these athletes will return to their pre-injury level of the sport. This demonstrates the significant effect that this injury has on an athlete’s future in the sport. Additionally, if an athlete returns to playing soccer, there is a high risk of further ACL injury (30%) to either the operative or nonoperative knee. ACL tears are also associated with the development of degenerative arthritis later in life. With the overwhelming impact ACL tears have on female athletes, screening and preventing injuries in this at-risk population is essential.

There is no secret that men and women are built differently. The reasons for females being more at risk for ACL injury have been extensively studied. The increased risk for injury appears to be associated with many factors, including a narrower intercondylar femoral notch and smaller ACL, an increase in natural ligament laxity, slower reflex time, an imbalance secondary to greater quadriceps strength and hamstring weakness, fluctuation in estrogen levels, and the tendency for females to land flat-footed.

The research has shown that ACL injury rates are influenced by the differences in the biomechanics of men and women. Key differences include:

• Landing position: When landing from a jumping position, female athletes tend to land with the knee in extension, which transfers the force of impact to the knee joint. Men tend to absorb more of the energy of impact by landing with their knees in a flexed position.
• Valgus alignment: Women have an increased knee valgus, and this alignment leads to more stress to the knee ligaments with activities.

Seventy percent (70%) of ACL injuries in female soccer players are noncontact and primarily involve one of two mechanisms: running and cutting sharply with an erect posture or landing with the leg in extension on one leg. Both mechanisms result in significant forces on the ACL, leading to ACL tears.

Soccer ACL injuries usually occur when the knee is in a position of extension for both contact and noncontact injuries. Video analysis of ACL tears during soccer has revealed some interesting injury trends. For noncontact ACL tears, female soccer players are more likely to injure their nondominant leg while men tend to hurt their dominant leg. Video analysis demonstrated that 75% of all soccer ACL injuries occurred while defending. Defending requires more cutting and stepping in to reach for the ball. Defensive play also has more off-balance landing on one foot as a cause of ACL tears. This frequently occurs with landing after a head ball and regaining balance after kicking. Both situations place the knee at risk the critical extended valgus position.

ACL prevention programs have been shown to decrease the risk for ACL tears by 70%.

Soccer Players Can Help Prevent ACL Tears

Fortunately, the factors that put females at a higher risk for ACL injuries can be modified. Soccer players and their parents need to take an active role in the prevention of ACL tears. Sportsmetrics and the PEP program (Prevent Injury and Enhance Performance) are two leading programs for ACL prevention. Dr. Cullen and Dr. Hopp have been advocates for these programs throughout their careers as they can decrease your risk for ACL tears by 70%. Leading research on ACL injury prevention was performed where Dr. Cullen did his training at Cincinnati Sports Medicine and Children’s Hospital of Cincinnati. Sportsmetrics was developed as a result of this research and stresses the importance of maintaining knee flexion and avoiding knee extension during landing to decrease landing stress on the ACL. Dr. Cullen has implemented this program at several high schools and has seen a significant reduction in ACL tears in our female athletes at these schools. They are well worth the time it takes to implement these programs as part of our soccer warm-ups and off-season programs. Katelyn Perkins, PT  highlights these programs in her article on ACL Injury Prevention.

About Dr. Cullen. Mark Cullen, MD is a board-certified orthopaedic surgeon and has completed advanced fellowship training in sports medicine and arthroscopic surgery. He has a passion for adolescent sports medicine. Before moving to New Hampshire in 2019, he was the team physician for numerous high schools and club sports teams throughout his career in Atlanta and Oregon. On the Seacoast, he works closely with high school athletic trainers, physical therapists, and coaches to care for athletes and prevent adolescent sports injuries. Having had four shoulder surgeries himself, he understands what an injury means to his patients and the time and dedication it takes to recover from surgery.