1 In Vivo Structural Analysis of Subchondral Trabecular Bone in Osteoarthritis of the Hip

Objective: With developments in clinical CT, in vivo analysis of patients ’ bone microstructure has become increasingly possible. The subchondral trabecular bone of hip osteoarthritis (OA) patients using multi-detector row CT (MDCT) was analyzed to closely examine the structural changes that occur as OA progresses. Design: 47 female hip joints were studied: 20 with OA secondary to hip dysplasia (11 advanced OA, 9 early-moderate OA), 7 with hip dysplasia without OA, and 20 normal. The images’ maximal spatial resolution was 280280500 m. Regions of interest were the subchondral trabecular bones of the acetabulum and femoral head. Measurement parameters were bone volume fraction (BV/TV), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), structure model index (SMI), trabecular bone pattern factor (TBPf), Euler’s number, and trabecular anisotropy (DA). Relationships between joint space volume and these parameters were analyzed. Results: With decreasing joint space, Tb.Th and BV/TV increased, and Tb.Sp, Tb.N, SMI, TBPf, and DA decreased significantly. The microstructures were significantly different betwee