Bone alterations at the subchondral level during rheumatoid arthritis (RA) remain under investigation. It remains unknown whether subchondral bone damage might still occur in RA patients in clinical remission, which could then infer suggesting that even minor subclinical inflammatory changes in the joint can induce local bone loss.
Thirty-two RA patients treated with biological disease-modifying anti-rheumatic drugs (bDMARDs) with low disease activity since at least 6 months and having erosion on the second or third metacarpeal head were enrolled in this pilot cross-sectional study. They were divided in two groups according to local inflammation assessed by Doppler-ultrasound exam surrounding the site of erosion. Cortical and trabecular parameters of the metacarpeal head were then assessed by high-resolution peripheral quantitative computed tomography (HR-pQCT) and compared in both groups.
Twenty and twelve RA patients were enrolled in the "Doppler positive erosion" (DE+) group and Doppler negative erosion (DE-) group, respectively. No difference was observed in their clinical or biological RA characteristics. Both cortical density and thickness were similar among groups. Within the trabecular network, while no difference in bone volume was observed, trabecular density as well as trabecular number were decreased (P<0.001 and P<0.05 respectively), whereas trabecular separation and distribution of trabecular separation were increased in DE+ compared to DE- (P<0.05).
In RA patients in low disease activity under bDMARDs, persistence of local inflammation was associated with alteration of the trabecular compartment. Trabecular density was the most strongly altered parameter and could be a candidate to assess drug effect on periarticular bone damage.