What is the ACL ?

Arthroscopic image of a normal ACL

Arthroscopic image of a normal ACL

The anterior cruciate ligament, or ACL is one of four of the
major ligaments that holds the knee together during routine activities and keeps it stable.  The ACL has a specific role in maintaining stability during cutting and pivoting activities, which as playing soccer and tennis.  Any activity when you try to cut from one direction to the other requires a solid functioning ACL.    Simple activities like walking on flat ground do not bring the ACL into play.  People who do not have a working ACL complain their knee feels unstable and won’t support them.  The symptoms are magnified when trying to step off a curb, walk on sand or uneven ground, or play sports.

How do I tear my ACL ?

The ACL can tear when it is stressed beyond its normal limits.  Most tears do not occur from contact by someone else or another athlete.  As mentioned above, it is a cutting activity that typically tears the ACL.  This occurs when you try to change directions suddenly by planting your foot and pushing off.  Most athletes complain of a loud pop, immediate pain, and are unable to walk.  Swelling usually following within a few hours.  Other ligaments and structures in the knee can be injured at the same time.

What should I do first ?

The first thing to do is to ice the knee immediately, and elevate the leg.  Typically ice should be used for 10 to 15 minutes, and then give the knee a break so you don’t freeze your skin.  An ACE wrap will also help with the swelling.  I encourage my patients to call me and get in to be seen as soon as possible.  Evaluation in the Emergency Room or at an Urgent Care may be helpful if I am not available and you are concerned.  I typically don’t encourage the use of knee immobilizers.  Crutches are often needed during the acute painful phase after an injury.  When comfortable, I encourage my patients to work on their range of motion and try to prevent stiffness.

How can I prevent an ACL tear ?

Prevention is always the best treatment !  Flexibility and strength conditioning specific to your sport will have a positive imp ace and decrease your risk of tearing your ACL.  The incidence of ACL tears is reported to be 5-6 times higher in women.  This is thought to be due to hormonal differences, the way women’s joints are shaped, and potentially due to differences in neuromuscular control of the thigh, gluteal and calf muscles.  This can be addressed by good coaching, training and understanding of the mechanics of your particular sport.

Do I need surgery for my ACL tear ?

Athletes who tear their ACL are usually active people who are not willing to eliminate activities that put the ACL at risk in the first place.  There are two simple options:  Have surgery to repair the ACL, or learn to live with the absence of it.  Those who accept the loss of the ligament typically stop playing sports, and lead a less active lifestyle.  I rarely find patients willing to accept this and want to keep going.  In most cases, surgical treatment is elected.

When will I return to activities after an ACL tear ?

The pain and swelling from an isolated ACL tear typically go away after 2-3 weeks with the appropriate treatments.  After surgery, most of my patients are out of school for a week and out of work for 2 – 4 weeks.  Phyiscal therapy is essential for maximal recovery.  Walking becomes fairly normal at 6 weeks, and many athletes return to sport between 6 and 12 months.  Return to sports is not just at a time point, but rather once functional goals have been reached.
Dr. Scott Hacker is a Sports Medicine Orthopedic Surgeon in San Diego, CA, Team Surgeon to the US Olympic Team.  He specializes in sports medicine and sports injuries, knee and shoulder surgery.
If you have questions about meniscus tears, or have a meniscus tear, please feel free to contact me at Ask Dr. Hacker or through my office.

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