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On the Mend: ACL Injuries and Prevention

June 12, 2017 12:00 PM with Dr. Eric Chehab

The ACL (anterior cruciate ligament) is one of the ligaments that keeps the bones in the knee connected; it’s also one of the most common places for the knee to be injured.

Athletes, casual fitness fans and those who stay active are at risk for tears and sprains from dangerous sports, bad exercise habits and even small casual accidents. Get in the know about ACL injuries and prevention with Dr. Eric Chehab, Affiliated Orthopaedic Institute Surgeon, who answers your questions about the ACL, how you can prevent injuries during your daily activities and the latest treatment options available.

Colie (Moderator) - 12:00 PM:
Our ACL injuries and prevention chat is now open. You can submit your questions at any time during this chat.

Dr. Eric Chehab (NorthShore) - 12:01 PM:
Welcome. I look forward to answering questions regarding ACL injuries and treatments.

Dr. Eric Chehab (NorthShore) - 12:02 PM:
And of course, prevention!

  Stacy (Arlington Heights, IL) - 12:02 PM:
Is surgery the only way to fix an ACL tear? Are there any permanent scars from the surgery?
Dr. Eric Chehab (NorthShore)
Hi Stacy - ACL injuries do not repair themselves, so yes, surgery is the only way to fix them, and any surgery will produce scars, but since the surgery is done arthroscopically, the incisions are typically quite small. The cosmetics is usually acceptable.

There are other ways to manage ACL injuries besides surgery, but those management strategies require lifestyle changes, and for young active patients, lifestyle changes can be quite difficult.

  Lisa - 12:06 PM:
is it a sign that there is something wrong when my knee seems to pop out on its own?
Dr. Eric Chehab (NorthShore)

Hi Lisa. Thanks for your question.

This is definitely a sign something is wrong. The knee should not pop out of place. That may be a sign of the kneecap being unstable and not tracking properly. It could be a sign of a ligament injury, such as to the ACL, or it might be your meniscus, which is a piece of soft cartilage that pads the knee. If it gets torn, it can get caught in the knee, making if feel like it pops out of place. These would be the most likely problems.

  Jaime (Evanston, IL) - 12:11 PM:
Do certain sports have more ACL-related injuries than others?
Dr. Eric Chehab (NorthShore)
Hi Jaime - yes, there are sports with higher rates of ACL injuries. The sports where there is a lot of jumping, cutting and decelerating tend to be related to a higher incidence of injury. I commonly see football, soccer, lacrosse and basketball players. Skiing is also quite common. It's not as common in baseball and softball, though Kyle Schwarber is an example of a baseball players injuring the ACL. Hockey also has a lower rate, but an ACL injury can happen in ANY sport, and so there's always a small risk. For instance, it would be rare for a marathon runner or cyclist to tear the ACL, as they would not be cutting and decelerating to cause the injury.

  Thomas (Chicago, IL) - 12:16 PM:
I have a question on prevention. When I do exercises that involve running or jumping, I experience soreness on the outer sides of my knees. What can I do pre-exercise (or between workouts) to prevent the soreness and/or future injury?
Dr. Eric Chehab (NorthShore)
Thomas - the most common cause of soreness on the outer sides of your knee is due to tightness of the muscles, particularly the IT band, so stretching the IT band can lead to pain relief. A physical therapist can show you how to properly stretch the IT band. I would focus my efforts on the stretching of those muscles to prevent soreness and future injury.

  Anna (Northbrook, IL) - 12:20 PM:
What can I do to prevent another ACL tear while actively playing on a soccer team?
Dr. Eric Chehab (NorthShore)
Hi Anna - This is an excellent question. You've already experienced a tear, and the research shows your OTHER knee is at risk. There are neuromuscular training programs that are quite helpful in reducing the risk of an ACL injury to your other knee, and re-injury to the involved knee. The focus is on training the muscles about your core, hip and knee to absorb shock and minimize energy through the knee. These programs are particularly effective. Bracing can be helpful as well, though the research results regarding bracing have been mixed. Some studies show bracing helps prevent re-injury, but others don't. My guess is, bracing PROBABLY helps, given the above. Those would be the two things I suggest you consider to prevent another ACL tear.

  Gordon (Bartlett, IL) - 12:27 PM:
Can elementary-aged children hurt their ACL? I’m signing my kids up for summer sports, and I don’t know if I should be worried.
Dr. Eric Chehab (NorthShore)
Gordon - The answer is yes, they can, but its not common. I would not worry so much about that. I think the important thing to focus on with elementary school children is the quality of the equipment, and the quality of the fields. Coaching is also important, with proper techniques. We can't prevent all injuries, and if I had the choice, I would not let the small risk of an ACL injury stop your child from participating. The benefits are much greater than the risks. As a side note, I injured my ACL as a 7th grader, which might explain why I became an orthopaedist, so there's always a silver lining!

  Caroline (Chicago, IL) - 12:30 PM:
How easy is it to tear your new hamstring ACL even months after surgery?
Dr. Eric Chehab (NorthShore)
Hi Caroline - Depends on how many months.... Normally, the ACL reconstructions, which use other tissues around your knee (hamstring, patella tendon or quad tendon), take a full year to mature. Once mature, the re-injury rates are at their lowest, so early on <6months, the ACL is vulnerable to re-tear if you do too much.

The rates vary depending on the type of reconstruction. For patella tendons, the rate is about 3-5%. For hamstrings, it's about 5-8%. Though one seems better than the other, the side effects are also quite different, so there's a lot to consider. It's important to complete the physical therapy after surgery, and to have the muscles protect the knee as the reconstructed ACL matures.

  Elizabeth (Chicago, IL) - 12:37 PM:
I'm 10 months after ACL reconstruction, and my knee still pops from time to time while I walk or run. Is this okay even several months after surgery?
Dr. Eric Chehab (NorthShore)
Hi Elizabeth - That's not unusual, but like all things, it depends. There is scar tissue that forms within the knee that can cause popping. If it's painful popping, or popping that makes your knee feel unstable, that should be evaluated by your surgeon. If it's popping associated with swelling of your knee, then that should also be evaluated by your surgeon. If it's popping you can hear, but doesn't hurt or cause the knee to feel unstable, that's QUITE common and usually benign.

  Kay (Wilmette, IL) - 12:41 PM:
A friend of mine had a diagnosis of gastrocnemius tear about a month ago. He still has pain occasionally, edema and is hard, but much better than a couple of weeks ago. Could this have anything to do with ACL?
Dr. Eric Chehab (NorthShore)
Hi Kay - There is no known association between gastrocnemius injuries and ACL problems. The gastrocnemius tears do take time to recover, and can sometimes recur. I nearly always recommend formal physical therapy for gastrocnemius injuries because it returns patients more quickly to their activity, and lowers their risk for re-injury.

  Christy (Chicago, IL) - 12:45 PM:
My son injured his knee, but didn't get an ortho appointment until we returned home and a couple weeks went by. We didn't know it was a torn ACL. In hindsight, I wonder what signs we missed, or if we should have taken him to an urgent care right away? Did he do more damage because he was walking around on it for a couple weeks?
Dr. Eric Chehab (NorthShore)
Hi Christy - I'm sorry to hear about your son. It can be hard sometimes to tell. I've had patients feel like they only "tweaked" the knee, and are surprised to find the injury was more involved. Hindsight is always 20/20, and it can be hard to tell if the ACL is injured. The usual signs of an ACL injury are knee swelling, the knee feeling unstable to the patient and the patient having felt a pop. Other than that, it would be difficult for non-health care professional to know. What I hope helps is that most patients with an ACL are not operated on right away, and do not do damage while walking on it. We always recommend evaluation as soon as you can, but it is VERY unlikely your son damaged his knee while awaiting evaluation. Again, most of the time, we delay the operation for a few weeks (or even months) to help the knee recover from the injury and feel more normal again before any operation is undertaken. Hope this helps alleviate concerns or parental guilt.

  Caroline (Chicago, IL) - 12:52 PM:
Is a brace absolutely necessary after surgery for returning back to sports?
Dr. Eric Chehab (NorthShore)
It is not absolutely necessary; however, I am one of those surgeons who recommends it for the first season back. There was a question earlier related to this, and the studies are mixed regarding bracing and its effectiveness for preventing re-injury. I do think athletes benefit from the brace to build confidence as they return. What I suggest to my patients is to use the brace for the first season back, and then I leave it up to the athlete for long term use. It's usually about a third to half of the athletes who like to use it over the long haul. Hope this helps.

  Ted (Round Lake Beach, IL) - 12:56 PM:
Are there any good tips for protecting the ACL before working out? I try to stretch before I do any activity, but I don’t know if I’m doing anything that helps my knees.
Dr. Eric Chehab (NorthShore)
Hi Ted - it depends on the workout. Most weightlifting activity or straight ahead activity is safe from an ACL injury standpoint. If you are doing a workout with running, cutting and decelerating, then yes, there are pre-workout activities that help. You may notice that teams are not doing so much static stretching, but are instead doing dynamic stretching. The dynamic stretching incorporates some of the neuromuscular training that helps protect the knee. Bottom line is to be sure to be warmed up, stretched particularly in the quads, doing a dynamic warm-up and not exercising until exhaustion.

Colie (Moderator) - 1:01 PM:
This will be the end of our chat. Thank you for your questions. For more information, please visit the NorthShore Orthopaedic Institute to make an appointment with Dr. Chehab.

Dr. Eric Chehab (NorthShore) - 1:02 PM:
Thanks everyone. Great questions.

This chat has ended.

Thank you very much for your participation.