ACL Injuries – Implications for the Female Athlete

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Abraham T. Shurland, MDby Abraham Shurland, MD

The Anterior Cruciate Ligament (ACL) is an important ligament that lies deep within the knee. Its job is to keep the knee together when you make twisting moves or sudden changes of direction that occur commonly in sports like football and basketball. Injury to this ligament often requires surgical repair. Most commonly, I use soft tissue reconstruction techniques that involve either a donated tissue allograft or hamstring tendon from the patient. Another technique that I use less commonly involves the use of the patella tendon. The best technique depends on a number of factors including the age of the patient and their level of expected post-surgical activity.

The occurrence of ACL injuries in female athletes has increased significantly with 1 in 100 experiencing injuries at the high school level and 1 in 10 experiencing injuries at the collegiate level. The rates of these injuries have increased for a number of reasons. First, the level of competition in female sports has increased significantly. Also, since the enactment of Title IX, female athletes have more options to play competitive sports and are starting at a younger age.

Many are surprised to learn that there are significant differences with how ACL injuries impact both male and female athletes. As a matter of fact, a recent study performed by the NCAA found that women athletes were 3 times more likely to injure their ACL’s than were male athletes. Other studies indicate that the female athlete is 4-8 times more likely to sustain an ACL injury than their male counterparts. Also, the sports with the highest occurrence of ACL injuries were female soccer and basketball. Furthermore, female athletes tend to have a higher rate of ACL injuries during match play as compared to practice.

We can all remember the video of Tom Brady tearing his ACL when a player from the other team fell onto his extended knee causing it to twist and hyperextend. This, of course, is an example of a contact injury and cost our quarterback a season on the sidelines. Perhaps the most intriguing piece of information is that the majority of ACL injuries with female athletes occur during non-contact situations, similar to what Wes Welker recently experienced. As a matter of fact, 93% of ACL injuries in the female athlete are non-contact.

Anatomical differences between male and female athletes help to explain why a female athlete is more likely to tear their ACL while simply changing direction or decelerating on a soccer field or basketball court. For example, when a female athlete lands from jumping, they tend to land on straighter knees. In this position, they are less likely to absorb the extreme forces of landing through their muscles. This excess energy can cause the knee to hyperextend or twist resulting in injury. Also, female athletes tend to cut or change directions on the field with knees that are straighter and hips that are less flexed. Again, this creates the potential for these excessive forces to be absorbed through the knee joint rather than through the supporting musculature.

There are a few other differences that make the female athlete more vulnerable to ACL injuries. For example, the joints in females tend to be more lax or flexible than males. This laxity puts more pressure through ligaments. Also, the ability for the knee to hyperextend is usually greater with females. Remember, the hyperextended position is often a contributing factor to the mechanism of ACL injuries. Perhaps the most significant difference between male and female athletes is how they use the muscles of the thigh during sports. Male athletes tend to be hamstring dominant. These large muscles on the back of the thigh are used to flex the knee and mimic the function of the ACL by preventing the shin bone from sliding forward. So, hamstring dominance helps to protect the knee. Conversely, female athletes tend to be more quadriceps dominant. The large quadriceps muscles are in the front of the thigh and extend the knee. This dominance may help to explain why female athletes land on straighter knees when jumping and change directions on the field with straighter knees. The space in the knee for the ACL is smaller in women than in men which may also contribute to tears.

There are specific things that can be done to prevent ACL injuries from happening in the first place. Improving balance, avoiding knock knee positioning during athletics and training, core strengthening, learning how to properly position yourself during activities, and improving the strength of your hamstrings are all examples of actions that can be taken to reduce injury. Starting your care with the evaluation of an experienced orthopedic physician is a great place to start. I am in hopes that you will never need and ACL surgery, but if you do, the team at Agility Orthopedics can provide you with the care you need.