Background Erosive hand osteoarthritis (EOA) is considered as an aggressive form of primary osteoarthritis that is defined radiographically by intra-articular erosions of the inter-phalangeal joints of the hand and characteristic deformities

Objectives To examine ultrasound (US) features of inflammation (synovitis, effusion, power doppler signal) in EOA joints, and to evaluate their relationship with radiological damage.

Methods Patients with clinical and radiographic diagnosis of EOA (American College of Rheumatology criteria [1]) formed our study group. Ultrasonography (Esaote MyLab 60 machine and a 13-18 MHz linear array transducer) and conventional radiographs (CR) of the hands were performed in all participants. The sonographer was a rheumatologist with theoretical and practical training in musculoskeletal ultrasonography. In B mode, effusion was defined with the OMERACT criteria [2]. In power Doppler mode (PD), the inflammatory activity was evaluated. A total of 720 joints were assessed by both radiographs and ultrasound (US): metacarpophalangeal (MCP) 1–5, proximal interphalangeal (PIP) 1–5, distal interphalangeal (DIP) 2–5 and trapezo-metacarpal (TM) joints.

Results A total of 24 women with EOA were recruited. The mean age was 59,6 years (range, 44-76). The average number of Heberden's and Bouchard's nodes were 3.8 (±2.9) and 1.5 (±1.8), respectively. 720 joints were scanned. Synovial hypertrophy was detected in 22 joints (3%), effusion in 79 joints (11%) and increased PD in 14 (2%) joints. Erosions were found in 89 (12.3%) small joints by US and in 152 (21.24%) small joints by CR (p=0.005). Osteophytes were detected in 137 (19%) small joints by US, and in 159 (22%) small joints by CR (p=0.5). Effusion was distributed between the PIP (91%) and DIP (9%), synovites between PIP (n=3), DIP (n=8), TM (n=7) and PD between PIP (n=3), DIP (n=6) and TM (n=5). A statistically significant correlation was found between effusion and osteophytes (r=0.3; p=0.05), PD signal and erosions (r=0.6; p<0.0001), PD and joint space narrowing (r=0.26; p<0.001).

Conclusions Both radiography and US may have a complementary role in detection and evaluation of EOA changes. US imaging appears to have a role in the detection of early EOA changes and provides additional information regarding erosion, osteophyte formation and synovitis compared to radiography and therefore supports the concept of EOA as an inflammatory arthritis.

References

1. Altman R, Alarcon G, Appelrouth D, et al. The American Rheumatology critera for the classification and reporting of the hand 1990;33:1601–10.

2. Wakefield RJ, Balint PV, Szkudlarek M, et al. OMERACT Special Interest Group. Musculoskeletal ultrasound including definition for ultrasonographic pathology. J Rheumatol 2005;32:2485e7.

Disclosure of Interest None declared

DOI 10.1136/annrheumdis-2014-eular.6003