Metal Form could overtake Titanium

Replacing bones and knees with tianium is the accepted standard today. New materials such a metal foam might be used to replace the rigid titanium. Researchers at North Carolina University are developing these new biomedical implants that have many benefits over titanium.
Titanium is relatively heavy compared to the metal foam. It is "even lighter than solid aluminum and can be made of 100 percent steel or a combination of steel and aluminum." In addition to the added weight, titanium is rigid. This modulus elasticity of the titanium is much larger than the bone. Modulus elasticity is the "material's ability to deform when pressure is applied and then returned to its original shape when pressure is removed." Titanium's modulus of elasticity is about 100 GPa. The metal foam has modulus "between 10 and 30 GPa" which is similar to bone. This means that titanium will take most of the load when a force is applied which causes the surrounding bone cells to die. Eventually the implant will loosen and will fail. The metal foam however has a rough surface allowing bone cells to grow within the foam and "will increase the mechanical stability and strength of the implant inside the body." The metal foam will not loosen within the bone thus making the replacement a better fix.
This article was interesting to me because I know several people who have had to have knee replacements. I knew these people were in pain before the operation and couldn't walk as well. After the surgery and rehablitation, their knees were almost as good as new. I didn't realize that the probability of another knee replacement is quite high if they put strenous pressure on their knees. I hope when I grow older, new methods of knee replacements will be available such as the metal foam. Walking and running without pain is taken for granted as a younger person, and I hope I can continue physical activity when I grow older.