Evaluation of a new erosion score by musculoskeletal ultrasound in patients with rheumatoid arthritisIs US ready for a new erosion score?

The objectives of this study are to evaluate a new semi-quantitative (0–5) musculoskeletal ultrasound (US) erosion score in patients with rheumatoid arthritis (RA) and to prove its usefulness in the detection of disease activity and success of therapy. Thirty-eight patients with RA (mean disease duration 10.1 ± 11.9 years) were enrolled. Start or change of therapy (DMARD/biologics) was an inclusion criterion. DAS28, laboratory (ESR and CRP) and US data were evaluated before new therapy initiation and after 1, 3, 6 and 12 months. Thirteen joints of the clinically more affected hand and forefoot (wrist and MCP, PIP, MTP joints 2–5) were analyzed for synovitis in grayscale (GS) and power Doppler (PD) US, tenosynovitis/paratenonitis in GS/PDUS (wrist, MCP level) and for erosions. Erosions were analyzed by a new semi-quantitative score (grade 0, no erosion; grade 1, <1 mm, grade 2, 1 to <2 mm; grade 3, 2 to ≤3 mm; grade 4, >3 mm; grade 5, multiple bone erosions). After 12 months, DAS28 decreased from 4.5 to 3.4 (p < 0.001), the synovitis score in GSUS from 26.3 to 12.8 (p = 0.001) and the synovitis score in PDUS from 10.6 to 4.1 (p < 0.001). The erosion score decreased from 21.5 to 18.1 (p = 0.046). There were longitudinal significant correlations between the new erosion score and both the DAS28 (r = 0.368; p = 0.025) and the synovitis score in PDUS (r = 0.365; p = 0.026) over a 1-year follow-up period. The new erosion score might be a useful tool for the evaluation of erosive changes by US in RA patients. In the course of DMARD and biologic therapy, it was responsive under 1-year follow-up examination.