High Failure Rate with MACT for Young Knees

Orthopedic surgeons from Italy report a high failure rate using matrix-assisted autologous chondrocyte transplantation (MACT) for young patients. Forty-four patients between the ages of 20 and 58 years of age with osteoarthritis from damage to the knee joint cartilage were included in the study.

Each one had a hole or defect in the joint cartilage that went all the way down to the bone. Symptoms of knee pain, swelling, locking and giving way and the formation of degenerative arthritis brought them in for treatment. Prior treatment failed and each one in the group was either too young for a joint replacement or did not want a prosthetic implant.

They were all treated with the MACT procedure with three goals in mind: 1) provide pain relief, 2) stop or at least slow the progression of osteoarthritis, and 3) eliminate the need for a joint replacement.

MACT is a three-step process: first normal, healthy cartilage cells are taken from a non weight-bearing area of the patient’s own knee. Then these cells are transferred to a lab where they are placed on a special scaffold. More cells are grown (forming a matrix). The last step is to implant the bioengineered tissue into the defect.

After the procedure, everyone had at 12 or more weeks of rehab. Follow-up was at least seven years with some patients being in the study for up to 10 years. These long-term results were disappointing as half the group said they were no better off than before the surgery. And almost 40 per cent said they wouldn’t do it again if they had it to do over.

The surgeons suggest that one of the factors that affected the results was previous treatment. Patients who had removal of part or all of the meniscus (meniscectomy) had the poorest clinical outcomes. It didn’t seem to matter whether the amount of osteoarthritis already present was mild, moderate, or severe. The reported results were the same for all levels of degeneration.

The surgeons concluded from this study that the use of a scaffold-based or matrix of bioengineered tissue to aid cartilage regeneration may not be advised in young adults. In particular clinical results were unfavorable in young adults with knee osteoarthritis who had prior knee surgery. In other words, matrix-assisted autologous chondrocyte transplantation (MATC) for knee osteoarthritis from this type of damage to the cartilage may not be the best salvage approach.

More research is needed to discover why this treatment did not work. It is possible the joint being damaged by degenerative arthritis just doesn’t have the right ingredients (environment) to aid in a healing response. MATC might work best for those individuals with cartilage lesions who have NOT had a previous meniscectomy. Further study is also needed to explore the limits of scaffold-based treatment for this type of problem in young adults.