Background Hand osteoarthritis (HOA) is one of the three most common subsets of osteoarthritis. So far, HOA diagnosis has relied on clinical (pain and finger joint nodes) and radiological features. Conventional radiographs (CR) can assess only subchondral bone. However, ultrasound (US) could detect synovial inflammation, even in the absence of clinically detectable signs of inflammation.
Objectives To describe ultrasound abnormalities in HOA in order to assess eventual association between these lesions and clinical symptoms.
Methods Patients at a hospital-based outpatient rheumatology clinic who met American College of Rheumatology criteria  for HOA were included. Demographic and clinical data (Visual analogue scale (VAS), the Australian Canadian osteoarthritis hand index (AUSCAN) pain, tender and swollen joint count) were collected for each patient. Ultrasonography (Esaote MyLab 60 machine and a 13-18 MHz linear array transducer) and plain radiographs of the hands were performed in all participants. The sonographer was a rheumatologist with theoretical and practical training in musculoskeletal ultrasonography and blinded to clinical features. The following joints were assessed: metacarpophalangeal (MCP) 1–5, proximal interphalangeal (PIP) 1–5, distal interphalangeal (DIP) 2–5 and trapezio-metacarpal (TM) joints. Allover, 720 joints were explored. In B mode, erosion, synovial hypertophy and effusion were defined with the OMERACT criteria. In power Doppler mode, the inflammatory activity was evaluated.
Results We included 24 women with symptomatic HOA between July and December 2013. Their mean age was 59,6 years (range, 44-76). All participants were right-handed. Median VAS and AUSCAN pain were 38mm and 7,5, respectively. Mean Dreiser algofunctional index was 8.03±6 (range, 1-19). Their mean symptom duration was 5 years (range, 1-20years), it consists in pain in 21 cases and stiffness in 8 cases. Mean number of Heberden's and Bouchard's nodes were 3,8 (±2,9) and 1.5 (±1,8), respectively. The average number of painful joint was either spontaneously at 2,08 (±5,45) or upon squeezing at 3.58 (±6,3) and with swelling at 0,33 (±0,7). Erosions were detected in 89/720 (12.3%) small joints by US and in 152/720 (24%) small joints by CR (p=0,005). Osteophytes were detected in 137/720small joints by US, and in 159/720small joints by CR (p=0,5). Thickened synovium was found in 22/720, effusion in 79/720 and increased power Doppler in 14/720small joints. Effusion were distributed between the PIP (91%) and DIP (9%), synovites between PIP (n=3), DIP (n=8), TM (n=7) and power Doppler imaging between PIP (n=3), DIP (n=6) and TM (n=5). The number of tender joint was significantly correlated with presence of an effusion by US (r =0.49, p<0.0001) but not correlated with a positive Doppler signal (r=-0.12, p=0.02).
Conclusions Our study showed that effusion is correlated with the number of tender joint. US detect inflammatory changes in small hand joints in the vast majority of patients with HOA. It suggests that current treatment modalities are inadequate treatment for this disease
Altman R, Alarcon G, Appelrouth D, et al. The American Rheumatology critera for the classification and reporting of the hand 1990;33:1601–10.
Disclosure of Interest None declared