A torn ACL (also known as the anterior cruciate ligament) is one of the most common knee injuries, with as many as 200,000 cases per year in the U.S. Young people under the age of 20 are at particular risk, in part because of participation in sports.
Despite the frequency of torn ACLs, many people don't know that the injury results in a significant risk of developing arthritis within 10 to . Around 70 to 80 percent of patients with a torn ACL will develop arthritis within that timeframe. Because most ACL injuries occur in young people, this means that arthritis could set in at a very early age. If a patient is 15 years old when she tears her ACL, for example, she could be struggling with arthritis by the age of 30.
The increased risk of arthritis is true regardless of whether the ACL tear is surgically repaired or not. The actual injury, and the knee's inflammatory response to the trauma, seem to be the culprits. The ACL is one of four main ligaments in the knee, connecting the thighbone to the shinbone, and any injury severe enough to tear the ligament is likely to affect other parts of the knee, as well. We also see bruises to the bone and damage to the cartilage, meniscus or other ligaments with about half of all ACL injuries.
At UK, doctors and researchers are currently trying to find ways to reduce the risk of arthritis by interrupting the inflammatory process in the week following the ACL injury. We hope that our research will lead to better long-term outcome for patients who experience ACL tears.
If you've torn your ACL in the past, be on the lookout for signs of arthritis in your knee. Symptoms include pain and swelling with activity. If you're experiencing these symptoms, it's best to consult an orthopedic sports medicine specialist, who will be trained in issues related to ACL injury and recovery.
If you've recently experienced an ACL injury, the most important thing for your recovery is adequate rehabilitation. The musculature around the knee joint is the biggest factor to prevent re-injury. The re-tear rate for ACL reconstruction under the age of 20 is around 20 to 25 percent, but a large portion of that can be prevented by being enrolled and trained in injury prevention rehabilitation.
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