Could the curse of arthritic knees be lifted? Scientists in the US are reported to have come up with a way of using electricity to stimulate new growth of cartilage, the tissue that acts as a cushion to stop bones rubbing together and causing pain. In successful experiments with rabbits, small mesh implants, about a half millimetre thick, generated tiny electric currents under the pressure of joint movement. The resulting electrical field prompted cells to colonise the implant and grow into new cartilage. It is hoped the technique may also herald relief from misery and avoidance of joint replacements for older humans.