Young people develop “old knees” after tearing the ACL
Within 10 years of ACL injury, about half of patients develop knee arthritis. The arthritis is called osteoarthritis, a disabling condition typically seen in old people who have knee pain, swelling and stiffness making it difficult or impossible to walk. Most people tearing the ACL are young and active, often teenage or college athletes who can then find themselves unexpectedly disabled early in life.
Osteoarthritis cannot be conventionally diagnosed until symptoms or x-ray changes appear and it is already too late to do anything to reverse its course, and there is currently no cure for osteoarthritis short of replacing the knee with metal and plastic. Consequently, Dr. Constance Chu has focused her research on new ways to identify “pre-osteoarthritis,” or signs of knee deterioration that occur before osteoarthritis even develops, as well as treatments that might prevent osteoarthritis.
When the ACL tears, it usually bleeds into the knee joint causing it to swell. The knee joint is not normally exposed to blood, and thus the bleeding triggers inflammation and other processes that can damage the joint cartilage. While outwardly, the knee may appear to recover and be symptom-free for years after, the inflammation and cartilage damage can persist and lead over time to osteoarthritis.
In an earlier award-winning series of more than 40 studies funded by the National Institutes of Health (NIH), Dr. Chu led research culminating in the development of a new MRI color mapping technique that can show early joint damage invisible to x-rays and standard MRIs. Through this new MRI technique, she found that nearly half of patients begin to develop “pre-osteoarthritis” just one to two years after ACL injury. This means that treatment may need to start as soon as the ACL injury occurs.