Medical Materials for the Next Millennium
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BULLETIN/MAY 1999
Survivability in year 2000
0 10 20 30 40 50 60 70 80 90 100 Age (yrs) Figure 1. Difference in human survivability in year 2000 versus 1900.
pact bone on the outside and a spongy or open weave of bone (called trabecular bone) on the inside that provides structural stability with very light weight (Figure 3). This provides an enormous surface area that helps maintain the metabolism of the rest of our body. In Figure 2, we see a schematic of the deterioration over time of the trabecular bone structure in men and women. The inserts show the progressive deterioration of the trabecular bone structure in the vertebrae or the hip of a 30-year-old vvoman, a 50-year-old woman, and a 70-year-old woman. The large amount of deteriora tion shown occurs in nearly half of the female population by 60 years of age. As can be seen, the thickness of the bone trabeculae has decreased by a factor of two or three times from its thickness at 20-30 years. Sometimes the thickness of the trabeculae disappears altogether, as shown by the arrows. Thus the crosssectional area of bone that Supports your weight can decrease to less than 50% with age, which causes the necks of hips in older people to shear off, long bones to fracture, and vertebrae to collapse. Such failures happen to hundreds of thousands of people in the world today. At the turn of the last Century, the only Solution to bone deterioration was to remain immobile, or—if sufficient damage was present, as from accident—to have the affected limb removed and artificial
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