This week, we will delve into one of the most common career-enders for professional football players – the dreaded ACL injury. Although football players are particularly susceptible to this type of injury, anyone who takes an impact of the knee at an oblique angle can damage their ACL.
The anterior cruciate ligament (ACL) is one of the four main ligaments within the knee that connect the femur to the tibia. The ACL helps stabilize the knee. An ACL injury is a tear in one of the knee ligaments that join the upper leg bone to the lower leg bone.
For clarity, the four main ligaments that connect these two bones are:
- Anterior cruciate ligament (ACL): is in the middle of the knee. It prevents the shin bone from sliding out in front of the thigh bone.
- Lateral collateral ligament (LCL): runs along the outside of the knee. It prevents the knee from bending out.
- Medial collateral ligament (MCL): runs along the inside of the knee. It prevents the knee from bending in.
- Posterior cruciate ligament (PCL): works with the ACL. It prevents the shin bone from sliding backwards under the femur.
If the knee joint is bent backward, twisted, or bent side to side, ACL can be injured. The chance of injury is higher if more than one of these movements occurs at the same time. Contact (being hit by another person or object) can also cause an ACL injury. These injuries can range from mild, such as a small tear, to severe, such as when the ligament tears completely or when the ligament and part of the bone separate from the rest of the bone. Women are more susceptible to this injury than men.
An ACL injury can cause knee pain, swelling, and weakness. Rest and physical rehabilitation are important to prevent a long-lasting knee problem. In some cases, surgery may be warranted.
We are going to begin a study of injuries to the anterior cruciate ligament (ACL). This week, we will explore the causes, symptoms, and risk factors for this traumatic injury.
ACL injuries often occur with other injuries. For example, an ACL tear often occurs along with tears to the Medial collateral ligament (MCL) and the shock-absorbing cartilage in the knee (meniscus).
Most ACL tears occur in the middle of the ligament, or the ligament is pulled off the thigh bone. These injuries form a gap between the torn edges, and do not heal on their own.
Causes
Ligaments are strong bands of tissue that connect one bone to another. The ACL, one of two ligaments that cross in the middle of the knee, connects your thighbone (femur) to your shinbone (tibia) and helps stabilize the knee joint.
Most ACL injuries happen during sports and fitness activities that can put stress on the knee. An ACL injury can occur if you:
- Suddenly slowing down and changing direction (cutting)
- Pivoting with your foot firmly planted.
- Landing from a jump incorrectly
- Stopping suddenly
- Receiving a direct blow to the knee or collision, such as a football tackle
Basketball, football, soccer, and skiing are common sports linked to ACL tears.
When the ligament is damaged, there is usually a partial or complete tear across the tissue. A mild injury
may overextend the ligament but leave it intact. Depending on the severity of your ACL injury, treatment may include rest and rehabilitation exercises to help you regain strength and stability or surgery to replace the torn ligament followed by rehabilitation. A proper training program may help reduce the risk of an ACL injury
Symptoms
Most people will know when they have received an ACL injury; they won’t be able to
Signs and symptoms of an ACL injury usually include:
- A loud "pop" or a "popping" sensation in the knee at the time of injury
- Severe pain and inability to continue activity
- Knee swelling that begins within a few hours
- Loss of range of motion
- A feeling of instability or "giving way" with weight bearing
- Pain, especially when you try to put weight on the injured leg
Those who have only a mild injury may notice that the knee feels unstable or seems to "give way" when using it.
Risk factors
Women are more likely to have an ACL injury than are men who participate in the same sports. Studies have suggested some reasons for these differences in risk.
In general, women athletes exhibit a strength imbalance in their thighs with the muscles at the front of the thigh (quadriceps) being stronger than the muscles at the back (hamstrings). The hamstrings help prevent the shinbone from moving too far forward — movement that can overextend the ACL.
Studies comparing jumping and landing techniques among men and women athletes have shown that women athletes are more likely to land from a jump in a way that increases stress on their knees. Research suggests that training to strengthen muscles of the legs, hips and lower torso — as well as training to improve jumping and landing techniques — may reduce the higher ACL injury risk associated with women athletes.
Complications
People who experience an ACL injury are at higher risk of developing knee osteoarthritis, in which joint cartilage deteriorates and its smooth surface roughens. Arthritis may occur even if you have surgery to reconstruct the ligament.
Multiple factors likely influence the risk of arthritis, such as the severity of the original injury, the presence of related injuries in the knee joint or the level of activity after treatment.
First Aid Measures
See your health care provider if you think you have an ACL injury. Do not play sports or other activities until you have seen a provider and have been treated.
Your provider may send you for an MRI of the knee. This can confirm the diagnosis. It may also show other knee injuries.
First aid for an ACL injury may include:
- Raising your leg above the level of the heart
- Putting ice on the knee
- Pain relievers, such as nonsteroidal anti-inflammatory drugs (such as ibuprofen)
You also may need:
- Crutches to walk until the swelling and pain get better
- Physical therapy to help improve joint motion and leg strength
- Surgery to rebuild the ACL
Some people can live and function normally with a torn ACL. However, most people complain that their knee is unstable and may "give out" with physical activity. Unrepaired ACL tears can lead to further knee damage. You are also less likely to return to the same level of sports without the ACL.
Next week, we will examine the treatment options for ACL injuries and the risks involved in this treatments. As always, if you have experienced a knee injury or knee pain please don’t wait for your family doctor. When you leave the emergency room, take the short drive to Gonzales, Louisiana and visit Excel Rehabilitation Services on Burnside Ave. You will receive personal care from a professional physical therapist!
Online Sources:
https://medlineplus.gov/ency/article/001074.htm
http://health.ccm.net/faq/3805-anterior-cruciate-ligament-definition
https://orthoinfo.aaos.org/en/diseases--conditions/anterior-cruciate-ligament-acl-injuries/
https://www.mayoclinic.org/diseases-conditions/acl-injury/symptoms-causes/syc-20350738