Which Stereological Methods Offer the Greatest Help in Quantifying Trabecular Structure from Biological and Mechanical Perspectives?

Mitchell B. Schaffler¹, David A. Reimann², A. Michael Parfitt¹ and David P. Fyhrie¹

¹Bone and Joint Center, Henry Ford Health Sciences Center, 2799 West Grand Boulevard, Detroit, Michigan 48202, U.S.A.
²Division of Radiologic Physics and Engineering, Henry Ford Health Sciences Center, 2799 West Grand Boulevard, Detroit, Michigan 48202, U.S.A.

(Received March 21, 1996; Accepted November 11, 1996)

Keywords: Trabecular Bone, Architecture, Stereology, Fourier Analyses

Abstract. Trabecular bone is a complicated interconnected network of rods, plates and sheets of lamellar bone tissue. Understanding its structure in terms of the elements that comprise the network and their architectural relationship to each other is key to understanding both the biological and mechanical attributes of trabecular bone in health and disease. Osteoblastic and osteoclastic activities in trabecular bone occur on bone surfaces. Surface activities in turn regulate trabecular bone mass and architecture, parameters which have great importance to mechanical function. Bone histomorphometry, based on classical stereology, has been used effectively and extensively to characterize bone cell-surface activities. Beyond measuring bone volume, however, the architectural parameters which need to be measured, and accordingly, the morphometric tools which are needed to describe the mechanical properties of trabecular bone, are less clear. Histomorphometric parameters designed to quantitate cell-surface activity do not yield direct information on the shapes of trabecular elements or architectural interrelationships, which are key factors influencing the mechanical properties of trabecular bone. Those stereological parameters used to predict mechanical properties of trabecular bone were not designed originally for that purpose. Applications of micro-computed tomography and micro-magnetic resonance imaging to trabecular bone provides three dimensional data; to date morphometric descriptors from these data have been extrapolated from standard two dimensional stereological applications. Availability of three-dimensional data presents an opportunity to extract new information about trabecular bone architecture, using morphometric tools designed specifically to measure mechanically relevant structural properties of trabecular bone.