OHSU Doctors Test Disc To Repair Knee Cartilage Damage
11/28/06 Portland, Ore.
Patient's own cells used to build bio-bandage for injury commonly associated with ACL tears
Oregon Health & Science University is leading a national effort to test a novel treatment for a little-known, but debilitating type of knee injury common among athletes and active individuals.
NeoCart, manufactured by Histogenics Corp. of Boston, is an investigational biological implant formed from a patient's own cells to replace cartilage damage resulting from a variety of knee injuries. One common injury associated with cartilage damage is tearing of the anterior cruciate ligament, or ACL, the central band of collagen tissue that stabilizes the shinbone, or tibia, and keeps it from sliding beneath the thighbone, or femur.
Dennis Crawford, M.D., Ph.D., assistant professor of orthopaedics and surgical director for Sports Medicine, OHSU School of Medicine, is the first surgeon in the country to successfully perform the NeoCart procedure in the first phase of a U.S. Food and Drug Administration clinical trial. Now, one year after all these research subjects have achieved return to activities, a second trial will be launched comparing this new technology to commonly performed micro-fracture surgery.
The NeoCart implant is a disc created by growing cartilage cells within a three-dimensional honeycomb matrix. The disc, or tissue bandage, is then sealed within the injury of the cartilage using a biologic glue. NeoCart replaces the damaged cartilage surface on the end of the bone inside the knee. The procedure is designed to allow the knee joint to resume gliding across the smooth area and, ultimately, absorb impact forces of activity.
Crawford, who serves as the lead investigator for the FDA trial, says the Neocart procedure has the potential to provide a substantial new clinical benefit.
"The aim of this technology is to restore normal hyaline cartilage on the joint surface, in areas where tissue has been damaged and otherwise does not heal," he said. "In contrast, the microfracture technique creates a scar cartilage. Using the NeoCart technology, the damaged cartilage is actually replaced by engineered tissue with the potential to heal. The intent of our study is to test whether Neocart allows joint healing, avoids joint degeneration and prevents future arthritis in comparison to microfracture, which appears to have only short-term, limited benefit."
The study now involves surgeons and researchers at the United States Military Academy at West Point; University of California, San Francisco; Hospital for Special Surgery in New York; and the Duke University Sports Medicine Center.
"There are several exciting aspects of this investigational technique that make it a significant advance from available surgical practices. This procedure can now be performed on an out-patient basis. One reason this is possible is the development and application of the bio-glue that eliminates the need for suturing the patch," Crawford added. "This seems to act a like a biologic Band-Aid."
Cartilage injuries often accompany ACL tears when sudden blows or twists to the knee can damage the joint. This is common among athletes in such sports as football, soccer, basketball, snowboarding and skiing. This type of cartilage injury appears as a small chip or tear in the joint surface that can feel mildly painful with standing or activity. Over time, the damage can scar, creating a rough surface on the cartilage that may manifest as degenerative joint disease or arthritis later in life.
Crawford says the function of normal cartilage is essential. "It's a thousands times slicker than ice," he said. "If it's injured, it doesn't heal well. If there's even a small defect, it may expand over time to become a painful, debilitating problem."
If a cartilage injury is detected through examination and a unique MRI process, patients can undergo a joint arthroscopy surgery. During this procedure, a micro-camera is used to examine the knee and evaluate the damaged cartilage. A pea-sized cartilage tissue sample is taken and sent to a laboratory, where the cells are grown into a NeoCart patch for six to nine weeks.
All study participants must meet several criteria, including passing an examination for the absence of arthritis as well as tests to determine whether they're allergic to a collagen used to grow the cartilage disc. After the cartilage patch is implanted during a similar outpatient surgery, subjects are directed to limit use of the joint and follow a specific rehabilitation program for several months. Subjects are evaluated periodically for improvements in knee function, and pain. MRI is used intermittently to monitor the healing process.
This randomized, controlled trial is designed to help doctors learn more about the application of this type of technology for the surgical management of knee joint injuries. One specific aim of the five-year study is to demonstrate that early treatment, in younger persons, is important in preventing future degenerative joint disease. Crawford said. "If NeoCart, or other technology like it, is proven safe and effective in clinical trials and approved by FDA, this could change the way we treat something once commonly thought of as simply a 'knee sprains.'"
Crawford emphasized the procedure is limited, still experimental, not an alternative to knee replacement, and is only designed for certain knee injuries and for injuries of certain sizes. As with any investigational product, there are potential risks, including risks associated with joint surgery, lower-than-expected cartilage cell function, and loosening of the implant.
NeoCart is limited by federal law to investigational use and is not available for sale.
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To access all OHSU news releases, visit www.ohsu.edu/news/ Dr. Crawford has an interest in Histogenics, the company that sponsors this study.
Dr. Crawford and the sponsor may financially benefit if the study is successful. This potential conflict was reviewed, and a management plan approved by the OHSU Conflict of Interest in Research Committee was implemented. Contact the OHSU Research Integrity Office at 503 494-7887 for more information.