Every year, approximately 1.7 million people in the U.S. and Europe tear a meniscus - children and athletes are especially prone to such injuries. But first, just what is a meniscus? It's one of two pieces of cartilage located inside each knee, that provide a cushion between the tibia and the femur. While smaller tears can heal on their own, larger tears often require a partial or complete removal of the meniscus. Within several years, this can result in the early onset of osteoarthritis. Recently, a new type of stem cell-seeded bandage, developed at the University of Bristol, has been approved for a clinical trial on meniscal tears. It may greatly reduce the need for menisectomies.

The treatment process begins with bone marrow being extracted from the patient's hip, using a needle. Stem cells are then grown from that bone marrow in a laboratory, and seeded onto a special membrane. That membrane is subsequently inserted into the tear, and the cartilage is sewn up around it to hold it in place. The idea is that the stem cells will proceed to become cartilage cells, and speed the regrowth of what might have otherwise been an unsalvageable meniscus.

The UK trial will see ten patients receiving the treatment, and then being monitored for a five-year period.

"The effective repair of meniscal tears would represent a significant advance in treatment, particularly for younger patients and athletes by reducing the likelihood of early onset osteoarthritis, and would offer an exciting new treatment option for surgeons," said Ashley Blom, Professor of Orthopaedic Surgery at the University of Bristol.

The cell bandage is now being produced by spin-off company Azellon Ltd.

A similar technology is being developed at Chicago's Northwestern University, in which a bio-active nanomaterial gel is injected into meniscal tears, stimulating stem cells to produce collagen.