Microfracture surgery due to a lack of studies on the long-term effects and the fact that an unsuccessful surgery could end an athlete's career. Dr. Steadman has also adapted the surgery into a treatment to help reattach torn ligaments (a technique he calls the "healing response") The surgery is performed by arthroscopy, after the joint is cleaned of calcified cartilage. Through use of an awl, the surgeon creates tiny fractures in the subchondral bone plate. Blood and bone marrow (which contains stem cells) seep out of the fractures, creating a blood clot that releases cartilage-building cells. The microfractures are treated as an
Effect of spaceflight on the human body responses of the human body in space. At the moment only rigorously tested humans have experienced the conditions of space. If off-world colonization someday begins, many types of people will be exposed to these dangers, and the effects on the very young are completely unknown. On October 29, 1998, John Glenn, one of the original Mercury 7, returned to space at the age of 77. His space flight, which lasted 9 days, provided NASA with important information about the effects of space flight in older people. Factors such as nutritional requirements and physical environments which have so far not been