The condition affects about 32 million Americans and happens when joints wear down over time.

Three research teams are working on new methods, mainly focused on knee osteoarthritis.

Two teams—one at Duke University and another at University of Colorado Boulder—are developing injections or infusions that may help rebuild cartilage and bone.

A third team at Columbia University is working on a more revolutionary idea: regrowing an entire knee using a 3D-printed “scaffolding” filled with bone and cartilage cells, The New York Times reported.