Q: I'm young and healthy but I have a bad knee. Dinged it up playing handball. Got a big hole in the cartilage that goes down to the bone. Too young for a knee replacement. Looking into these new treatments with Matrix cartilage transplantation. What does this do? How does it work? Does it work? What can you tell me?

A: When you say "matrix cartilage" treatment, we assume you are referring to matrix-assisted autologous chondrocyte transplantation (MACT). There are three goals in mind when using this procedure: 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.

According to a recent study from Italy, clinical outcomes using this treatment in young adults with knee osteoarthritis from cartilage damage may be disappointing. They treated 44 patients between the ages of 20 and 58 years of age who had osteoarthritis from damage to the knee joint cartilage.

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.

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. 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. Your orthopedic surgeon is really the best one to advise you based on your age, condition of the knee, your activity level, and what you hope to achieve from treatment.

Reference: Giuseppe Filardo, MD, et al. Matrix-Associated Autologous Chondrocyte Transplantation for Cartilage Regeneration in Osteoarthritic Knees. In The American Journal of Sports Medicine. January 2013. Vol. 41. No. 1. Pp. 95-100.