Today, one of my friends who is writing the final version of his thesis called me to ask about a quote from Prof. Ashby that I used it in my public defence. I wish to share it with you:
When modern man builds large load-bearing structures, he uses dense solids: steel, concrete. When nature builds large load-bearing structures, she generally uses cellular materials: wood, bone. There must be a good reason for it.
Michael F. Ashby
How does osteoporosis change the the mechanical properties of tibia bone? where are the major changes, in cortical layer or in cancellous bone? and is this about change in the density or the cortical layer thickness?
Voila, my short conclusion:
Osteoporosis is a condition in which the bone mineral density and consequently its strengths are decreased. Because osteoblasts and osteoclasts inhabit the surface of bones, cancellous bone is more active, more subject to bone turnover and remodeling[wiki]. It makes us to understimate the important role of the cortical bone in osteoporosis phenomenon. Lower overall bone mass, lower thickness of cortical bone and lower bone mineral density increase the failure risks of revision knee surgery. But age does not change these parameters (no statistically significant correlation) and smoking does.
