Why Are Females More Prone To ACL Injuries?

Worldwide studies have shown that female athletes have a significantly higher rate of ACL injuries compared to their male counterparts. Women are 2-4 times more prone to ACL tears. The difference in the anatomy between men and women would explain the reason to this. It would be interesting to know that there are more than contributing factors that increase the risk of ACL injuries in women. Read on to find out. 

What is an ACL Injury?

The knee joint is composed of 3 bones – Femur (thigh bone), Tibia (shin bone), and Patella (kneecap). These bones are held together by ligaments (tissues that connect two or more bones). The 4 cruciate ligaments that connect these bones are anterior, medial, lateral, and posterior cruciate ligaments.  The ACL is located in the center of the knee and helps to stabilize the joint by preventing the tibia (shin bone) from sliding out in front of the femur (thigh bone). An ACL injury is caused due to the partial or complete rupture of the anterior cruciate ligament.

What causes ACL injury?

An ACL injury is caused by the rupture of the anterior cruciate ligament that connects the thigh and shin bone. The rupture may be caused due to various reasons such as: 

• A sudden impact on the ACL from twisting the knee or landing on one leg
• A direct collision with another individual, where the knee is directly hit
• Stopping suddenly while running
• Changing the course of direction abruptly
• Repeated stress to the knee

Other factors include falling off a ladder, a car accident or missing a step on a staircase.

Why are Females More Prone to ACL Injuries?

There isn’t a clear explanation for why women are more prone to ACL injuries than men are, but many orthopedic surgeons believe that it is due to a combination of anatomical and biomechanical differences between men and women.

1. Women Typically have a Wider Pelvis than Men 

Women have a wider pelvis than males, which causes the thigh bones to narrow down sharply and exert pressure on the inside of the knee. This pressure is directed toward the ACL, causing it to rupture.

2. Women have a Narrow Intercondylar Notch

Women also have a smaller ACL and a very narrow intercondylar notch (the groove in the thigh bone through which the ACL passes). This narrow notch can limit the movements of the ACL, placing extreme pressure on it, and resulting in an ACL tear.

3. Female Hormones do Play a Part 

Ligament elasticity is linked to low levels of progesterone and estrogen hormones. These hormones are at low levels during the first half of the menstrual cycle, causing the ACL to be less rigid (more elastic) and prone to tear. There are hence four times more chances of the ligament getting torn during the first two weeks of menses. 

4. Women are Quad-Dominant 

The two main muscles that are used for movements are the quadriceps (from muscles of the thigh) and tbe hamstrings (back muscles of the thigh) and they must be used equally for stabilization of the knee. In women, the quadriceps muscles are stronger and more used than the hamstring muscles (due to their anatomy and structure) – this is known as quad dominance. This leads to the hamstrings becoming weak and more prone to injury, not only of the ACL but also of the lower leg, ankle, and foot, as the force of both muscles is needed to stabilize the knee.

5. Women are More Flexible than Men

Bodies move and react differently in females than in males. Women have more elastic ligaments. It is this flexibility that increases the chances of the ACL (ligament) being stretched and twisted, resulting in a torn/ruptured ACL. 

6. Women Tend to Land in a Flat-Footed Position

Women are more likely to land on a flat foot from a jump rather than landing on the balls of their feet. The resulting pressure is unevenly distributed and the shock is mainly absorbed by the knee, resulting in the ACL rupture.

7. Women Tend to Fall in Knee Valgus Position

Females often fall to the ground in a knee-valgus position after landing from a jump. Knee valgus occurs when the knees move inward toward the midline of the body and are no longer parallel to the hip and ankle. This position puts extreme pressure on the knees, causing the ACL to rupture.

 

8. Women have Low Muscle Mass Around their Knees Compared to Men

Women often have less muscular strength in their knees, which might impair knee mobility and result in knee give out, increasing the chance of ACL injury.

What Can Women Do to Decrease Their Risk of ACL Tears?

Sports injuries can occur despite taking all necessary safety procedures. However, certain preventative measures may be taken to lower the risk factors. Here are some tips for women to lower the risk of ACL injuries. 

1. Strength Training: Your knee joint is composed of the tibia, femur, and patella bones that are connected by 4 ligaments that provide stability to the knee joint. ACL ligament being one of them runs diagonally through the knee joint and is responsible for the rotational movements of the knee. Bones, ligaments, and muscles of the knee joint, if weakened can predispose you to ACL injuries. Strength training targets your ACL and other muscles and should be done regularly to strengthen the musculoskeletal system around the knee. Women should start building up their calves and  hamstrings as they are already quad-dominant.  Hamstring curls, jumping and agility exercises should be done to strengthen and stabilize your knee, thus preventing ACl injuries.
2. Balance Training: You should engage in balancing exercises that increase their ability to maintain balance and know their limbs’ position at a particular moment (proprioception). Neuromuscular exercises must be added to the daily regime as it helps in training your nerves and the muscles to react and communicate with each other. These exercises will enable them to balance and land safely when required, thus preventing ACL injuries from occurring.
3. Using Proper Gear: The appropriate gear for a particular exercise is important as it enables you to perform the exercises comfortably. Improper footwear (poor-fitting shoes) can hamper your balance and increase your risk of tripping, twisting, or falling, resulting in ACL tears. Ensure you wear proper athletic gear and shoes while working out to prevent ACL injuries.
4. Regular Stretching: You should never forget the warm-up and stretching exercises before starting a strenuous workout. If you are returning to workouts after a long time, the muscles and ligaments that are cold and stiff would be more at risk of getting injured. Warming up and stretching  before the workout will help in loosening these muscles and thus prevent injuries to the ACL. You should focus on the hamstrings and quadriceps muscles for strengthening but also should work on the rotational muscles of the ankle as when twisted may cause the leg and the knee to twist, thereby resulting in an ACL tear.
5. Avoiding High-Risk Activities: You should avoid high-impact exercises/ activities that can lead to pain and discomfort, like jumping, running, and squatting, as they cause pressure on the knees.

• Maintaining a Healthy Weight: You should reduce unwarranted strain on your knee joint and keep a check on your weight to prevent ACL injuries. Your body mass index (BMI) is an indicator of your fitness. It takes into consideration of your height and the corresponding weight that you should have to maintain a healthy body. You must also eat a well-balanced and nutritious diet regularly to prevent putting on weight as the increased weight will transmit all the excess weight to the knee joint. Your knee with excess pressure and weight, may give way, leading to ligaments and muscle injuries.

Takeaway

The difference in the anatomy, biomechanics and hormones makes females more prone to ACL injuries. Women need to take steps to reduce their risk of ACL injury, such as incorporating strength and conditioning programs, proper warm-up and cool-down routines, and proper technique training in sports and physical activities. Additionally, seeking prompt medical attention and proper rehabilitation following an ACL injury can help ensure a successful recovery. Contact us at Medfin for any queries on ACL injuries or ACL reconstruction. Our expert team of doctors can guide you on the right treatment and rehabilitation measures.