They end up bent double, on zimmer frames, with pain, particularly pelvic fractures which are almost impossible to control in terms of pain.

BBC: Breakfast with Frost

When it is damaged -- sometimes congenitally, or as result of disease, pelvic fractures or other traumas -- it is usually replaced using tissue harvested from the lining of a patient's cheeks or using skin grafted from another area of the body, according to Atala.

CNN: Scientists 'seed' cells, make new organs