The objectives of this study were: (i) to develop a standardized method of quantifying bone mineral density (BMD) and microarchitecture in the hand and wrist bones of patients with rheumatoid arthritis (RA) using high resolution- peripheral quantitative computed tomography (HR-pQCT); (ii) to compare quantitative bone parameters between RA and post-menopausal osteopenic (PM-OP) subjects; and (iii) to correlate quantitative bone parameters at the distal radius with those at the metacarpal heads in RA subjects.
HR-pQCT imaging of the dominant hand and wrist was performed in 12 female RA patients. BMD and trabecular parameters for the 2-12% head region of the second and third metacarpals were calculated and compared between RA patients and healthy controls. Bone parameters were also calculated for 110 slices of the distal radius in RA patients and compared to data from controls and PM-OP women from a previous study.
Compared to controls, RA patients had significantly decreased BMD, trabecular volume and number, and increased trabecular heterogeneity in the third metacarpal and distal radius. Significantly lower trabecular number and significantly higher ratio of outer annular trabecular BMD to inner trabecular BMD were observed in patients with RA, compared to patients with osteopenia (P < 0.05). Trabecular BMD in the third metacarpal and in the distal radius were significantly correlated (ρ = 0.918, P < 0.0001) in RA patients.
This study established a standardized method for quantifying bone density and trabecular properties in the hand and wrist bones of RA patients using HR-pQCT. Deterioration of bone structure in RA patients was found comparable to that in osteopenic women, and trabecular bone loss near affected joints was found to be correlated with bone loss away from joints.