difference between ACL and MCL tears

What’s the difference between ACL and MCL tears?

Knee injuries rank among the most common sports-related injuries. Whether you play high school football, hit tennis balls on the weekends or enjoy jogging or hiking to clear your mind, anyone is at risk of injuring their knee at any age.

As weight-bearing joints that endure a lot of impact, participation in sports is not a prerequisite for knee injury. you don’t even have to participate in substantial physical activity to injure your knees. And as we age, the risk only increases.

Two of the most common knee-related injuries are ACL and MCL tears. Though you’ve undoubtedly heard the acronyms used before, what’s the difference between them? Understanding how these injuries occur can help you take steps to prevent them or at least reduce the risk of getting hurt.

Understanding the Knee Ligaments

The first step to understand the difference between ACL and MCL tears is to first understand the complexities of the knee.

While there are four major knee ligaments, the two most common injuries involve either the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL).

The MCL serves the purpose of providing medial stability to the inside of our knee and the ACL prevents anterior, or forward, translation of the tibia. It is very possible to injure both ligaments, in addition to other important structures in the knee, at the same time.

Roughly 70% of ACL injuries are non-contact related that involve sudden deceleration such as cutting, pivoting or landing on one leg. Sports that often require these types of movement include basketball, soccer, football, volleyball, downhill skiing, lacrosse, and tennis. This type of injury can also happen as a result of a direct blow to the outside of the leg or knee.

The MCL is torn by a force to the lateral side of the leg, forcing the ligament to tear as the femur and tibia are separated in the joint line. This can happen playing contact sports such as football, sports that quick stops and turns such as soccer or basketball, or even a non-sport related slip and fall. MCL tears can also occur as a result of repeated stress, which causes the ligament to lose its normal elasticity much like a worn-out rubber band.

Difference Between ACL and MCL Tears

These ligaments differ most based on their location in the knee joint. The MCL is a superficial ligament that is surrounded by the musculature of the medial knee. The ACL, however, is deep within the knee and stands as the main stabilizer of the joint because it has no muscle directly surrounding it.

When the ACL tears to any extent, the stability it provides to the knee is completely compromised, causing a great deal of instability that makes activities like running and walking downstairs very difficult.

The MCL does provide additional stability but the joint does not suffer greatly without it, as long as the demands of the individual do not require a great deal of stability on the medial aspect of the knee. Activities that require this additional support for proper function are usually athletic in nature, such as kicking a ball.

Signs and Symptoms

One of the most common signs of a knee ligament tear is hearing an audible “pop.” Even if you don’t hear this sound, you can typically feel a sudden shift in the joint. Other common symptoms of an ACL or MCL tear include:

  • Knee instability
  • Swelling
  • Pain, which can range from mild to severe
  • Tenderness
  • Feeling that the injured knee may give way under stress
  • Feeling that the injured knee may lock or catch

Severity of ACL and MCL Tears

Both are extremely painful but may result in a number of different treatment options, depending on the severity of the tear.

A ligament tear is classified according to the following criteria:

  • Grade 1 – stretching of the ligament
  • Grade 2 – partial tearing of the ligament
  • Grade 3 – complete rupture of the ligament

A grade 1 or grade 2 tear of the ACL may be surgical but can be treated non-operatively, at times, with conservative rehabilitative interventions. In most cases, an MCL tear will not warrant surgery unless it is a full grade 3.

How ACL and MCL Tears are Treated

The type of treatment required for ACL or MCL tears will depend on a variety of factors including the severity of the tear, age, and personal medical history.

If you take the necessary steps in allowing a torn ACL or MCL ligament to heal, in some cases surgery may be avoided. However, if the injury is severe enough, there is always the possibility that surgery will be necessary.

For an MCL tear, the first step in the healing process is rehabilitation, or physical therapy. Therapy can take two or more months before the ligament is fully healed. It’s important to be patient and not rush this process, otherwise, you may risk further damage or reinjury.

An ACL injury is more complex due to the fact there are multiple ligaments within the ACL. In more than half of injuries involving an injured ACL it won’t heal by itself and will often require surgery, with an estimated 350,000 ACL reconstructions performed annually in the United States. During this procedure, called ligament reconstruction, tendons from the patellar or hamstring are used to reconstruct the ACL ligament. The recovery time for this type of surgery is 8-12 months.

When to Seek Help

Knee injuries are very common when it comes to all sports and physical activities, but most cases aren’t serious. Identifying a severe knee injury and acting quickly by having a sports medicine physician look at it can make all the difference when it comes to getting you back on your feet and minimizing the risk of further damage.

The signs and symptoms of an ACL or MCL tear are not always the same, so it is important to see a doctor if you experience knee pain or swelling that lasts more than 48 hours, trouble standing or walking on the affected knee, inability to support your weight on the affected knee, or noticed a deformed or odd appearance of one side of the knee compared to the pain-free side. If you experience any of these symptoms, call Paris Orthopedics and Sports Medicine at (903) 737-0000 to schedule an appointment today.