This image shows stem cells (stained green) growing throughout the pores of a three-dimensional, biodegradable, woven scaffold (stained red), which was designed to fit over the ball of the patient’s hip joint. The stem cells were taken from fat beneath the skin and were seeded onto the scaffold. Using a cocktail of growth factors, the stem cells were coaxed into turning into cartilage cells, where they regenerated cartilage throughout the woven scaffold, while the scaffold slowly dissolved. The newly formed cartilage can be used to completely resurface an arthritic joint. The engineered cartilage also releases anti-inflammatory molecules to keep arthritis at bay. This process may lead to treatments for hip osteoarthritis that avoid the need for extensive hip replacement surgery. To see the resulting cartilage-covered scaffold, see “Stem Cells Engineered to Grow Cartilage” at www.flickr.com/photos/niams_nih/28302085163/in/album-7215...