A successful executive in his mid-40s, Derek Johnson was an avid athlete. He enjoyed running, working out and playing basketball, until one day in 2005 he injured his knee during a game. As the pain progressed he started having trouble maintaining his normally active lifestyle.
"When Derek first came to see me, he was experiencing progressive pain in his knee that had begun to severely limit his ability to be active," said Riley Williams, MD, an orthopedic surgeon in the Sports Medicine and Shoulder Service at Hospital for Special Surgery, and Director of the Institute for Cartilage Repair at the hospital. "When we did magnetic resonance imaging, or an MRI, we saw that he was losing cartilage in a very localized area of his knee."
Dr. Williams first prescribed physical therapy to strengthen the knee, but it didn't help Derek with the pain. Surgery was the next option and because Derek was under 50 years old and the area of his cartilage injury was very localized, Dr. Williams considered Derek as the perfect candidate for a multi-center randomized cartilage repair trial looking at a new way of repairing cartilage that he is leading at HSS.
During arthroscopic surgery on Derek's knee, Dr. Williams confirmed the damage that the MRI had shown and then took two pieces, about the same size as two pain pills, from healthy cartilage in the knee to be sent to a lab where the cartilage cells could be isolated and then grown to a larger number.
A new type of protein matrix, which has an internal structure shaped like a honeycomb, was then seeded with the cells. The cells use the structure as a scaffold and begin to grow over and around it to eventually create a piece of new cartilage.
"About six weeks after the initial arthroscopy, we implanted the new cartilage into Derek's knee," said Dr. Williams. "The new cartilage was cut to fit the damaged area and then glued into place, much like a living patch that will eventually integrate seamlessly with the surrounding cartilage. We took another MRI three months after the surgery to check the new cartilage and everything looked fine."
Derek was on crutches for about a month after the surgery and is currently in physical therapy. The total recovery time after this surgery is about six months. Dr. Williams plans to follow up with him throughout the first two years and then another check-in at five years to track the implant's long-term success.
While other types of cartilage repair procedures exist, Dr. Williams is impressed by this method's technical simplicity over other repair methods. "Using the healthy cartilage cells gives the cartilage the building blocks it needs to promote healing over the long term," said Dr. Williams. "And using the patient's own cells lowers the chance of complications and difficulties after the surgery."
The multi-center cartilage repair trial is being held at six investigational sites around the United States and will test up to 30 patients between the ages of 18 and 55 to compare, on a randomized basis, the new technology with other standard treatments. The data will be used to evaluate safety, the efficacy of the implant, identify appropriate patient populations and help inform future clinical trial design. Patients return for follow-up visits after 10 days, six weeks, three months, six months, one year, and then annually for the next five years.
To learn more about the clinical trial, please see the news story "Options Available for Cartilage Repair May Expand with New Clinical Trial"