Osteoarthritic versus osteoporotic bone and intra‐skeletal variations in normal bone: Evaluation with µCT and bone histomorphometry

Several studies have shown that in contrast to osteoporosis (OP), osteoarthritis (OA) is characterized by high bone mineral density (BMD). Bone strength not only depends on mineral content as determined by dual X‐ray absorptiometry (DXA), but also on bone microarchitecture. We studied intertrochanteric bone from normal controls and OA and OP patients by bone histomorphometry (BHM) and microcomputed tomography (µCT) as well as DXA in order to first, test the differences between OA and OP comparing both groups to healthy controls, second, to assess variations between three different skeletal sites in controls and third, to determine the level of agreement between µCT, BHM, and DXA. Analysis was performed on 115 samples from OA and OP patients, and controls. We found significant differences between OA and OP samples in structural parameters and in the osteoid fraction (p < 0.05). The majority of the intra‐skeletal differences were shown between lumbar spine and femoral head samples (p < 0.05). Significant agreements were found between µCT and BHM and DXA (r = 0.32–0.45, p < 0.05). Our findings suggest differences in intertrochanteric bone between OA and OP, the age‐related intra‐skeletal variations and a correlation between microscopic and macroscopic bone evaluation methods. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1059–1066, 2013