Contributor: Kurt Spindler, MD
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The thought of tearing the anterior cruciate ligament (ACL) in the knee strikes fear in the heart of an athlete, as it often is a season-ending injury.
ACL tears are one of the most common of all knee injuries, with more than 200,000 occurring annually. The number of ACL tears in younger athletes has increased dramatically in part because of the growth of competitive sports.
If you need surgical reconstruction of your ACL, several choices must be made. Recent research points to one factor that should be carefully weighed when you and your doctor discuss treatment options: your age.
What is the ACL?
The ACL connects the thigh and shin bones that meet inside your knee. The ACL helps stabilize the knee, and protects it from shifting or rotating out of place.
ACL injuries usually result from a sudden stop or change in direction, an incorrect landing or direct contact such as a collision. ACL injuries are common in sports with stop-and-go movements, such as soccer, football, basketball and gymnastics.
Most ACL injuries are complete tears, where the ligament splits in two, making the knee unstable.
Not all tears require surgery. You doctor may recommend surgery if:
- You are young and active
- You are an athlete and want to continue to play your sport
- Your knee has more than only ACL damage
- The injury causes pain or affects everyday activities
ACL tears cannot be stitched back together. Instead, surgeons replace the ligament with one of two types of tissue grafts, an autograft or an allograft.
An autograft comes from your own body, usually a tendon from the kneecap or hamstrings. An allograft involves a tendon taken from a deceased donor.
Both graft sources have advantages and disadvantages that you should thoroughly discuss with your surgeon.
Why age matters
The initial reconstruction of a torn ACL is likely to have a positive outcome. Recent research shows that the patient’s age and the type of graft can predict the chance of success of a first-time ACL reconstruction.
Those studies indicate that younger, more active patients are less likely to have their ACL reconstruction fail when an allograft is used.
Allograft reconstructions fail in about one in every five 18-year-old patients. In contrast, autografts fail in about one in every 17 18-year-old patients.
As a patient’s age increases, however, so does the chance of success with an allograft. Researchers aren’t sure why.
By age 40, there is virtually no difference — less than 2 percent — in the failure rate of an allograft versus an autograft.
So if you are facing ACL reconstruction, it’s important to ask your doctor about the risk of failure specifically for someone of your age and activity level.
If that reconstruction fails — meaning the ligament is reinjured or ruptured within two years — the outlook for a second surgery is not as good.
What to expect after ACL reconstruction
After surgery, rehabilitation plays a vital role in restoring knee strength, stability and motion. Physical therapy may be long and rigorous, and involves:
- Restoring motion to the joint and muscles
- Strengthening the knee to protect the new ligament
- Returning the function you need for your sport or work
You also will learn preventive measures to lessen the chances of re-injury. These may include proper warm-ups, how to land correctly from a jump and strength training to firm your muscles.
If ACL surgery is in your future, carefully review the risks, benefits and rehab needed with your physician. Based on the research, your age and activity level should be a part of that discussion.