ACL vs. MCL: What You Need to Know About Knee Injuries

You’ve seen it often enough on TV – a pro football player who hurts his knee is being carted off the field. Knee injuries are common in many sports, sidelining elite and casual athletes alike.

It’s one of the most alarming injuries an athlete can experience, something that sports medicine specialist Michael Salata, MD calls an “acute event” that usually happens in a game-stopping single play.

Often the injury is damage to the knee’s stabilizing ligaments – either the medial collateral ligaments (MCL) or the anterior cruciate ligaments (ACL).

Your MCL is the ligament that gives stability to the inner knee, while the ACL, which is located in the center of the knee, controls rotation and forward movement of the tibia, or shin bone.

“When this kind of injury happens, the player needs immediate evaluation by the team trainer,” Dr. Salata says. “If the injury appears severe, the athlete needs further evaluation by an orthopedic surgeon or a non-operative sports medicine physician.”

If you’re not part of a team or aren’t certain what do when you injure your knee, Dr. Salata answers these common questions athletes have:

How do I know if I seriously injured my knee?

Many people who injure their knee will hear or feel a pop. If you have swelling and pain after the pop, that can mean a serious injury, Dr. Salata says.

“Swelling occurs quickly because a ligament tear bleeds into the knee,” he says. “You need to seek medical attention right away.”

Other signs of post-pop injury include stiffness and inability to do normal activities that involve twisting or turning at the knee. The knee may buckle or become unstable.

Until you’re seen by your doctor, be sure to “RICE” your knee:

• Rest
• Ice it to reduce swelling
• Compression using an elastic bandage or brace
• Elevation

What steps should I take to avoid injuring or re-injuring my knee?

According to Dr. Salata, knee injuries are ever-present – and sometimes unavoidable – in almost every sport. He recommends you try:

• Wearing a protective knee brace during exercise: “The debate goes on about whether or not bracing is effective for minimizing ligament injuries,” he says. “No definitive evidence exists that it makes a difference, so it’s up to the athlete.”
• Doing muscle-strengthening exercises: Training programs can teach you how to land from a jump that can help decrease the risk of an ACL injury. Female athletes are more prone to injury, largely due to how they land on their feet. Studies have demonstrated that proper strength training and technique decreases ACL injuries.
• Limit your activity and allow your knee time to heal.

If I tear my ACL or MCL, is surgery always necessary?

While knee injury pain hurts, you don't always require surgery in order to heal and get back to your sport. If you’ve injured your MCL, rehab therapy is usually the first course of treatment. Recovery can take two months or more.

ACL injuries are more complicated, mainly because more ligaments are involved. In general, an ACL injury doesn’t heal itself and often requires surgery for ligament reconstruction. Additionally, these ligaments can’t be sewn back together, so grafts – typically from the patellar or hamstring tendons – are necessary. It can take eight to 12 months before you’re completely healed.

"Even though recovery can feel like it’s taking a long time, there’s hope," Dr. Salata says. "The majority of athletes – in the low to mid-90 percent – eventually return to their activities after an operation,” he says.

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