Testing artificial hip. Equipment being used to investigate stress shielding in a prosthesized (artificial) hip. Stress shielding is where stress is transferred from the bone to the implant. This reduces the load on the bone, which is then broken down by the body as 'not needed'. This results in loosening and failure of the joint. Solutions to the problem include using composite materials for the implant that mimic bone flexibility. The head of the prosthesis, seen emerging from the bone, is held by the clamp at upper centre. Photographed at the Rizzoli Institute, Bologna, Italy.