Wednesday, March 12, 2008
Falling and hip fractures
Dr. Mary Bouxsein, a biomechanical engineer at Harvard, defines a fall as a "sudden, unexpected event that results in a person coming to rest on a horizontal surface."
She and others have studied the dire consequences of such events to aging skeletons. While prevention of bone loss is a major focus of medical research on osteoporosis, equally important is the prevention of fractures in bones already thinned by the disease. Research has shown that a sideways fall is almost six times more likely to cause a fracture in an osteoporotic hip than pitching over in any another direction. Healthy adult volunteers falling in research labs have shown why.
Only two of six subjects were able to get their arm out in time to break the impact of the fall. For the others, hip impact occurred first, with almost all of the force delivered on a path directly through the bone. As expected, overweight fallers delivered a larger impact to their hip. Even though the fat pad overlying the hip bone absorbs some of the impact energy, it is probably not enough to prevent a fracture when a large but frail lady comes to rest on the floor.
"Trochanteric padding systems" (a girdle-like garment with padding over the hips) have been developed to decrease the destructive impact of sideways falls to fragile old ladies. One study, however, found that women were reluctant to wear them because of how they looked.