Preventing ACL Injuries In Female Athletes

A sudden twist of the knee can result in a torn or ruptured anterior cruciate ligament (ACL).  This can be from an awkward fall or a sporting injury. An ACL tear is one of the most common knee injuries and can happen to anyone. However, studies have shown that adolescent girls are up to eight times more likely to have an ACL injury than adolescent boys.

Where Is ACL In Your Knee?

The ACL is a ligament, or short band of tough, flexible connective tissue that hold the bones of the knee together. The ACL is in the center of the knee. Its job is to control rotation of the bones of the knee and prevent forward movement of the shin bone (tibia) on the thigh bone (femur).

The ACL is one of four major ligaments in the knee that give the joint stability and strength. The other three structural ligaments of the knee are:

• Posterior cruciate ligament (PCL): This ligament is in the back of the knee. It controls backward movement of the shin bone.
• Medial collateral ligament (MCL): This ligament gives stability to the inner knee.
• Lateral collateral ligament (LCL): This ligament gives stability to the outer knee.

How Do Knee Ligament Injuries Happen?

Knee ligament injuries can be caused by trauma, such as a car accident, or they can be caused by sports injuries. Quickly changing direction, pivoting, slowing down when running, or landing from a jump can put the knee at risk for an ACL tear.

Sports that put the knee at risk include (but are not limited to) skiing, basketball, volleyball, soccer and football.

Oftentimes people will feel a "pop" in their knee with immediate swelling at the time of the injury. Once the swelling improves, there may be a feeling of the knee "giving way" with changing directions or even simple walking. There are several factors that put athletes at risk for an ACL tear. These include weak muscles, poor flexibility, lack of control/balance with sporting activities.

Ligaments that are injured are considered “sprains” and are graded on a severity scale.

• Grade 1 Sprains: The ligament is mildly damaged and has been slightly stretched but is still able to help keep the knee joint stable.
• Grade 2 Sprains: The ligament is partially torn and may create a feeling of some instability.
• Grade 3 Sprains: This type of sprain is a complete tear of the ligament. The ligament has been split into two pieces, and the joint is unstable.

How Common Are ACL Injuries?

The ACL is one of the most common ligaments to be injured. The ACL is often stretched or torn during a sudden twisting motion. The most common way this happens is when the foot is planted and the knee twists inward. The knee can feel like it “pops out of place” during this type of movement.

According to the American Academy of Orthopaedic Surgeons, about half of all injuries to the anterior cruciate ligament occur along with damage to other structures in the knee, such as articular cartilage, meniscus, or other ligaments.

What Are Symptoms Of An ACL Tear?

When you injure your ACL, you may hear a “popping” noise and you may feel your knee give out from under you. There are other symptoms that you may experience.

• Pain with swelling
• Loss of full range of motion
• Tenderness along the joint line
• Discomfort while walking

If any of these symptoms occur, you need to see your doctor. Your healthcare provider will ask you your health history and do a physical exam. You also may need one or more of these tests:

• X-ray: This imaging test can rule out an injury to bone instead of a ligament injury. It uses energy beams to make images of internal tissues, bones, and organs on film.
• MRI: This test uses large magnets, radio waves, and a computer to make detailed images of organs and structures within the body. It can often find damage or disease in bones and a surrounding ligament, tendon, or muscle. It is the best way to diagnose a ligament injury of the knee prior to a potential surgery.
• Arthroscopy: This procedure is used to diagnose and treat joint problems. The healthcare provider uses a small, lighted tube (arthroscope) put into the joint through a small cut (incision). Images of the inside of the joint can be seen a screen.

Do ACL Injuries Require Surgery?

Treatment for an ACL injury varies depending on the patient symptoms, age, and general health. It will also depend on how severe the injury to the knee is. ACL treatment may be surgical or non-surgical.

• Nonsurgical treatment: An ACL tear will not heal without surgery, but nonsurgical treatment may be effective for patients who are elderly or have a very low activity level.
• Surgical treatment: The ACL will be reconstructed using tissue from a different part of the body or from a donor. The new ligament is used to replace the damaged ligament. In rare circumstances, the ACL can be repaired.

Why Do Females Have More Ligament Injuries?

“Women have a statistically greater chance of sustaining a knee ligament injury than a male,” said Lauren Dorn, MS, LAT, ATC, sports medicine manager for Franciscan Health Lafayette.

In the 1980s and 1990s, research focused on dealing with an epidemic of ACL injuries in women athletes.

“Title IX provided women greatly increased opportunities to participate in college sports, so many more women began to participate in higher level athletics,” Dorn said. “At that time, the training and injury reduction techniques were not as advanced as they are now. As a result, by the mid ’80s we were seeing a large number of ACL injuries in college level women athletes.”

Women's Knees Are Different

One reason females have more ACL injuries is due in part to differences in women’s anatomy.

The ACL passes through a “notch” in the lower end of the thighbone that forms part of the knee. The ligament is about the same size for a woman as a man - but the notch is up to 20% narrower in women. That makes the woman's ligament more susceptible to tearing.

Muscle Imbalances Set Females Up For Injury

“There tends to be a lot of imbalance in strength of the muscles of the thigh, which can make women more prone to injury,” said Emily Krodel, MD, primary care and sports medicine with Franciscan Physician Network Primary Care & Sports Medicine Lafayette.

A woman’s hamstring muscles, at the back of the thigh, are often weak compared with her quadriceps, the muscles at the front of the thigh. The quadriceps pull the bones of the lower leg forward, and the hamstrings pull them back. Hamstring muscles help protect the ACL from injury. When the pulling power is out of balance, the knees suffer.

This muscle imbalance tends to be far worse in women than in men. The imbalance may begin to happen during childhood if girls engage in less physical activity. Exercising in the right way can help overcome the problem.

Hormones Impact Ligaments

Hormones also may play a role in ACL injuries. During menstruation, girls release hormones such as estrogen and relaxin. This causes laxity or looseness of the ligaments and makes them more prone to injury. Risk of injury to the ACL appears to be higher during ovulation, when estrogen levels are highest. The ACL appears to respond to estrogen by decreasing cell activity to repair basic ligament fibers called collagen.

“Don’t assume your daughters’ coaches know this,” Dr. Krodel said. “Parents must be proactive about ensuring their daughters’ coaches fully understand these issues.”

How Can I Prevent ACL Tears?

Dr. Krodel recommends that girls participate in training that strengthens muscles and stretches their hamstrings. Girls should also take part in agility training where they learn to properly run and shift directions, as well as strengthen their core muscles. It is important to avoid the knees becoming “knock-kneed” during jumping, landing, or changing directions.

Hamstring Curls

Lying on your belly, draw your lower legs upward, and try to touch your heel to your buttock. Use resistance equal to about 10% of your body weight. Do a few sets of 10 to 15 repetitions; hold them a second or 2.

Jumping Exercises

Jumping exercises are also critical for building strength and preventing knee injuries. When you land from a jump, keep it soft. Come down on the balls of your feet and slowly roll back to the heel.

Keep your knees bent and your hips straight. Try to keep your knee in line with your foot.

Hopping over a cone side to side and forward and backward builds strength and control:

• Place a 6-inch cone on your left. Hop over the cone with both feet, concentrating on a soft landing. Repeat by hopping back over the cone to the right. Repeat for a total of 20 hops.
• Place the cone in front of you. Hop over the cone with both feet, then hop backward over the cone. Keep your knees slightly bent when you land. Repeat for a total of 20 hops.
• Repeat the above forward and backward exercise, but hop with 1 leg at a time. Again, keep your knee slightly bent when you land. Do 20 hops on each leg.

By The Numbers

According to SafeKids.org:

• One in three children who plays a team sport is injured seriously enough to miss practice or games.
• Girls are up to eight times more likely to have an ACL injury than boys.
• 62% of organized sports-related injuries happen during practice.
• The most common types of sports-related injuries among children are sprains, muscle strains, bone or growth plate injuries, repetitive motion injuries and heat-related illness.