Dependence of trabecular structure on bone quantity: a comparison between osteoarthritic and non-pathological bone.

The mechanical characterization of trabecular bone is related to its structure. In order to describe the trabecular structure and to study the mechanical behavior of the trabecular tissue, several parameters are presented in the literature. Some studies suggest a possible dependence of the structure on bone volume fraction; this dependence could bias the validity of previous studies. The problem increases its complexity when pathological bone such as osteoarthritic tissue is studied, where the organization of the trabecular structure could be different if compared to the non-pathological tissue. The primary aim of this study was to evaluate the dependence between trabecular structure and bone volume fraction. The secondary aim was to compare osteoarthritic and non-pathological bone considering the correlation between structure and bone volume fraction.Sixty trabecular bone specimens were extracted from femoral heads of two groups of 30 Caucasian donors; an osteoarthritic group and a non-pathological group. Several structural parameters, such as bone volume fraction, direct trabecular thickness, fabric tensor eigenvalues and their normalizations, were calculated from micro-CT analysis. A statistical analysis was carried out to identify the dependences between structural parameters and bone volume fraction. The comparison between osteoarthritic bone and non-pathological bone was also performed.Only the normalized eigenvalues of the fabric tensor were not correlated to bone volume fraction (R<0.5). The first and second normalized eigenvalues were significantly different between osteoarthritic bone and non-pathological bone (respectively P<0.05 and P<0.001).In conclusion, orientation and anisotropy of the trabecular structure do not depend on bone volume fraction. Moreover, differences in the first and second normalized fabric tensor eigenvalues suggest in the osteoarthritic group a structure more oriented along the main trabecular direction.