Novel stem cell therapy for repair of knee cartilage

Dec. 29, 2018

Mayo Clinic offers a unique regenerative medicine approach for repairing knee cartilage, which can be completed in a single surgery. The Food and Drug Administration approved the use of this technique, known as recycled cartilage auto/allo implantation (RECLAIM), in a trial utilizing the stem cell bank in the Mayo Clinic Center for Regenerative Biotherapeutics.

"Mayo is unique in having an adipose-derived allogeneic stem cell bank. It provides us with donor mesenchymal stem cells, which we mix with recycled autologous cells to quickly obtain enough cells to fill the patient's cartilage defect without operating twice," says Daniel B. Saris, M.D., Ph.D., an orthopedic surgeon at Mayo Clinic in Rochester, Minnesota, who specializes in knee surgery and focuses on regenerative medicine.

Dr. Saris previously performed the RECLAIM cartilage repair technique in Europe. "The results, about four years out, are very good — comparable to or better than other cell therapies, except these patients achieve normal function after surgery about six months more quickly," he says.

Planning is underway for a clinical trial at Mayo Clinic. RECLAIM is used to repair symptomatic cartilage defects, usually resulting from trauma or an athletic injury. The procedure might be suitable for nonarthritic patients ages 18 to 50 who have fresh cartilage defects.

Recycling patient cells

Existing cell therapy to repair knee cartilage generally involves surgically debriding the cartilage defect and then taking a biopsy of healthy cartilage from the patient. The biopsy is cultured in an outside laboratory, and the cultured cells are implanted weeks later. "We wanted to improve this technique because during the waiting period, the patient's life is on hold, costs increase and the logistics can be complex," Dr. Saris says.

RECLAIM's innovation starts with saving the patient's debrided tissue. "That tissue is always a bit frilly and is normally discarded," Dr. Saris says. "But we found that the cells in that tissue are still very viable. We recycle them."

The resected tissue is processed and, using a rapid isolation protocol, digested into chondrons. Mixing the chondrons with allogeneic stem cells from the stem cell bank provides sufficient cells to immediately re-inject into the patient.

"This is a highly innovative procedure," Dr. Saris says. "You have to find an intricate balance — loading enough cells to grow into healthy tissue but not overloading the space so the cells are squished when the patient starts rehab."

Most patients return home on the day of surgery. They generally need to wait nine to 12 months before a full return to sports; that interval provides time for the cartilage to grow and the patient to regain muscle control. "But apart from sports, patients can go back to normal life within days and physical activities within three to four months of surgery," Dr. Saris says.

Mayo Clinic's multidisciplinary approach provides the range of care needed by patients at all stages of knee cartilage repair. Before surgery, advanced imaging helps pinpoint the cartilage defect. "Our physiotherapists and athletic trainers also determine prior to surgery how we can optimize the patient's musculoskeletal control and function, and then work with the patient on rehab after surgery," Dr. Saris says.

Mayo Clinic also has the breadth of orthopedic expertise to manage problems that patients often experience alongside damaged knee cartilage, such as varus deformity and anterior cruciate ligament or meniscus lesions. "If a cartilage repair procedure fails, it's generally because not enough attention was paid to other factors — the meniscus or the knee's alignment or stability," Dr. Saris says. "Our unique multidisciplinary team looks at all aspects of a patient's care. Our chances of success for these complex biological reconstructions is therefore high."

The cartilage repair technique illustrates Mayo Clinic's commitment to applying regenerative medicine to orthopedic surgery. "We are focused on patient-centered progress," Dr. Saris says. "We want to make sure there is a safe and efficacious portfolio of regenerative medicine therapies for musculoskeletal problems."