Cross-sectional DXA and MR measures of tibial periarticular bone associate with radiographic knee osteoarthritis severity

Abstract

Objective We evaluated the relationship of medial proximal tibial periarticular areal bone mineral density (paBMD) and trabecular morphometry and determined whether these bone measures differed across radiographic medial joint space narrowing (JSN) scores. Methods 482 participants of the Osteoarthritis Initiative (OAI) Bone Ancillary Study had knee dual X-ray absorptiometry (DXA) and trabecular bone 3T magnetic resonance imaging (MRI) exams assessed at the same visit. Medial proximal tibial paBMD was measured on DXA and apparent trabecular bone volume fraction (aBV/TV), thickness (aTb.Th), number (aTb.N), and spacing (aTb.Sp) were determined from MR images. Radiographs were assessed for medial JSN scores (0–3). We evaluated associations between medial paBMD and trabecular morphometry. Whisker plots with notches of these measures versus medial JSN scores were generated and presented. Results Mean age was 63.9 (9.2) years, BMI 29.6 (4.8) kg/m2, and 53% were male. The Spearman correlation coefficients between DXA-measured medial paBMD and aBV/TV was 0.61 [95% confidence interval (CI) 0.55–0.66]; between paBMD and aTb.Th was 0.38 (95%CI 0.30–0.46); paBMD and aTb.N was 0.65 (95%CI 0.60–0.70); paBMD and aTb.Sp was −0.65 (95%CI −0.70 to −0.59). paBMD and the trabecular metrics were associated with medial JSN scores. Conclusion The moderate associations between periarticular trabecular bone density and morphometry and their relationship with greater severity of knee OA support hypotheses of remodeling and/or microscopic compression fractures in the natural history of OA. Longitudinal studies are needed to assess whether knee DXA will be a predictor of OA progression. Further characterization of the periarticular bone in OA utilizing complementary imaging modalities will help clarify OA pathophysiology.

MRI texture analysis of subchondral bone at the tibial plateau

“…Radiographic indices of subchondral bone integrity have previously been associated with increased cartilage thickness[10] and decreased risk of progressive joint space loss [9]. Previous MR studies have demonstrated alterations in microstructural trabecular morphometry measurements between volunteers and individuals with OA [13,14], and that such measurements correlate well with severity of OA [15]. Proposed mechanisms of alteration in SB architecture include entry of inflammatory infiltrates via vascular channels in the SB [37] and increased deposition of subchondral marrow lipids [38].…”

“…Previous studies evaluating SB have used 3D isotropic gradient echo sequences in order to allow calculation of conventional trabecular microstructural parameters [14,15]. Our study used 2D high spatial resolution T1 weighted sequence designed to maximise signal-to-noise ratio due to increased slice thickness compared with 3D sequences.…”

“…MR quantification of SB architecture to date has focused on trabecular microstructural analysis [12][13][14][15], although alternatives including semiquantitative grading of subchondral sclerosis [16] and MR signal heterogeneity analysis [17] have been attempted. While initial results from these techniques 5 have been promising, a number of issues remain.…”

An OA phenotype may obtain major benefit from bone-acting agents

“…Digital X-ray, computerized tomography, and MRI are useful imaging techniques for a meticulous assessment of subchondral bone integrity in RCTs [75][76][77][78][79][80]; however, they are not suitable for daily clinical practice due to technical difficulties. In contrast, the simultaneous use of dual X-ray absorptiometry (DXA), to assess subchondral bone density [71,[81][82][83][84][85], and bone scintigraphy [76,77,[86][87][88][89], to detect patients on high subchondral bone remodeling, sounds reasonable in daily practice (Table 1). Scintigraphy would be an excellent marker to assess the de novo rate of subchondral bone remodeling, thus acting as a surrogate marker, whereas DXA would provide an index of accumulative Table 1 Main studies demonstrating the potential of subchondral bone mineral density and scintigraphy as screening tool and outcome measurement in knee OA.…”

Characterization of knee osteoarthritis-related changes in trabecular bone using texture parameters at various levels of spatial resolution—a simulation study

“…Increasing efforts have been made to develop imaging biomarkers on the basis of conventional radiography 5,14-18 and MRI [19][20][21][22][23][24] to quantify subchondral bone architecture changes in vivo and microCT has often been used to assess trabecular structure in bone specimen. [25][26][27][28] However, to the best of our knowledge, only one study used CT to OA-related changes in trabecular bone T Lowitz et al investigate the structure of subchondral trabecular bone in vivo in human OA hips.…”