Ultrasound evaluation of finger joint cartilage damage progression in patients with rheumatoid arthritis.

BACKGROUND

Cartilage damage in rheumatoid arthritis (RA) is commonly evaluated by joint space narrowing (JSN) on conventional radiograph (CR). Cross-sectional studies suggest that ultrasound (US) can directly assess finger-joint cartilage damage; however, whether it can sufficiently evaluate cartilage changes over time remains unclear.

OBJECTIVES

This study aimed to investigate temporal changes in cartilage damage in patients with RA using US.

DESIGN

A single-center, retrospective observational study.

METHODS

Fifty-three patients with RA underwent US scans of finger joints and CR of both hands at baseline and 1 year later. Cartilage thickness was measured at the bilateral second to fifth metacarpophalangeal and proximal interphalangeal joints, and cartilage damage was semiquantitatively scored using recorded US images. JSN was scored on CR using the van der Heijde-modified Sharp method. Patients were grouped by disease activity over 1 year, assessed by Disease Activity Score of 28 joints with C-reactive protein. Continuous variables were analyzed using the Mann-Whitney U or Wilcoxon signed-rank test. Correlations were assessed using Spearman's rank correlation coefficients.

RESULTS

Median patient age and disease duration were 68 and 6.3 years, respectively. Baseline total cartilage thicknesses of 16 joints ranged from 3.1 to 9.1 mm (median, 6.5 mm). Total semiquantitative scores were 0-22 (median, 5). Cartilage thickness (rho, -0.63; p < 0.001) and semiquantitative (rho, 0.67; p < 0.001) scores were significantly correlated with JSN scores. Patients with sustained moderate-to-high disease activity showed greater cartilage thickness reduction (median, -6.2%) than others (median, -1.2%; p = 0.004), although semiquantitative (21.6% vs 16.7%, p = 0.74) and JSN (0% vs 0%, p = 0.68) scores remained unchanged. The two groups differed significantly in the amount of change (-0.4 vs -0.1 mm, p = 0.006).

CONCLUSION

US detected cartilage damage progression in RA over 1 year, supporting its usefulness for longitudinal assessment.