Depending on the part of the body and the nature of the injury, cartilage either doesn't grow back at all, or does so very slowly. That's why joint injuries often take a long time to heal, to the point that scientists are looking into using things like hydrogels and 3D printers to help speed the process. Now, however, researchers from Switzerland's University of Basel are reporting that cartilage cells harvested from a patient's own nose can be used to grow replacement cartilage for their knee.
In the ongoing study, 6 mm-wide plugs of cartilage are being taken from test subjects' nasal septum (the bit inside the nose, that separates the nostrils). Cells are extracted from that tissue, multiplied in the lab, and then applied to a piece of biocompatible scaffolding-like material.