Improving Meniscus Surgery

In the United States, a torn meniscus is the most common reason for knee surgery. These two C-shaped pieces of cartilage distribute body weight across the knee joint and are responsible for stability and cushioning.

While damage to the tissue can sometimes be repaired, in other cases all or large parts of the meniscus must be removed and replaced by cadaver tissue. These implants do not appear to function as well or last as long, possibly because the patient’s own cells do not grow into the central portion of the tissue. As a result, there are no cells there to maintain the tissue’s structure and strength.

Julie Steen, B.S., a biomedical engineering student, works with advisers Cristin M. Ferguson, an assistant professor of orthopaedic surgery and regenerative medicine, and Mark Van Dyke, PhD, an assistant professor of regenerative medicine, and a team of researchers toward the development of an improved meniscus scaffold that could be used as an alternative to current methods when the meniscus must be replaced.

The project’s goal is to incorporate a patient’s own cells into the donated tissue to improve its function. To accomplish this, the team first processed donor menisci from an animal model to remove the cells, leaving behind the support structure. The processing also had an additional function: to increase the porosity of the tissue. An important part of the work was to determine the ideal level of porosity, enough to encourage the growth of cells in the tissue, but not too much to weaken the tissue. The next step was to attempt to “grow” cells on the scaffold, which was performed in culture stem cells found in bone marrow.

“The decellularization process didn’t change the integrity of the meniscus and did result in increased porosity,” said Steen. “Results from our animal study are promising. It appears our new approach to transplants decreases osteoarthritis occurrence and the tissue is able to maintain its integrity in vivo. These results are promising and suggest that this technique may provide an alternative to allograft transplantation.”

Further research is needed, including refining seeding techniques to achieve uniform cell density and adding culture conditions that support meniscus tissue differentiation.

Next Project

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As co-researchers in the Armed Forces Institute of Regenerative Medicine, WFIRM researchers are applying the principles of regenerative medicine to projects aimed at helping injured soldiers.

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