One of the most common and difficult to treat injuries affecting athletes and the elderly is a tear in the meniscus of their knee. And according to the American Academy of Orthopedic Surgeons, nearly 1 million people every year must undergo surgery to repair this part of their body.
The problem is acute because torn cartilage does not repair itself easily, and even after multiple treatments and surgeries the problem is not always fully resolved. In addition, multiple treatments often lead to arthritis, and eventually knee replacement surgery.
Fortunately, the results of a promising new treatment involving the use of stem cells to regrow cartilage has been published in Science Translational Medicine that details the method.
The process involves the 3D-printing of a model of a meniscus using the “same biodegradable plastic found in surgical sutures.” This replica is then filled with a type of protein that attracts stems cells from nearby bone marrow. Researchers also apply special growth factors to the replica, which helps provoke the stem cells to develop the collagens and fibers that “spur the stem cells to develop into the specialized collagens and fibers that make up cartilage.”
Although human trials have not begun, researchers pioneering this method have tested the process in sheep, an animal whose knee joints are remarkably similar to the knees of humans.
Researchers surgically attached these biodegradable plastic molds to the meniscus of seven sheep. Twelve weeks later, new patches of cartilage regrew and the sheep fully regained their mobility.
Of course, there is much more work and testing to be done, and although regrowing a meniscus will provide relief to millions of human sufferers, regrowing the cartilage that pads the bones beneath the meniscus will prove much more difficult to solve.