Sub-Micron 3D Fluorescent Imaging and Visualization of Remodeling Cavities in Cancellous Bone

The mechanical properties of cancellous bone are determined from a combination of bone quantity (volume), the material properties of the mineralized tissue, and microarchitecture. Bone remodeling is the primary process through which bone mass and structure are altered in the adult skeleton. Bone remodeling involves the coordinated activity of osteoclast and osteoblast cells, which resorb and then form bone at an isolated location on the cancellous bone surface. Because bone resorption precedes formation, each bone remodeling event in cancellous bone is associated with a temporary void on the bone surface known as a remodeling cavity. It has been proposed that remodeling cavities can act as stress risers, modifying stress distributions in cancellous bone and potentially impairing bone strength, stiffness and other mechanical properties. While high resolution finite element modeling supports the idea that remodeling cavities have the potential to modify mechanical properties at the micro-scale (in individual trabeculae) [1] and at the apparent level (entire cancellous bone specimens)[2, 3], the experiments required to confirm these findings are limited because a repeatable method of quantifying the number and size (length width and depth) of remodeling cavities in entire cancellous bone specimens has not yet been demonstrated.