To study inflammatory ultrasound (US) features and pain over a 3-month period in hand osteoarthritis (HOA).
In 25 consecutive HOA patients (mean age 60 years, 76% female), fulfilling the American College of Rheumatology (ACR) criteria, visual analogue scale (VAS) pain scores were collected at baseline and 3 months. In 750 [all first carpometacarpal (CMC), metacarpalphalangeal (MCP), proximal interphalangeal (PIP), distal interphalangeal (DIP) and first interphalangeal (IP)] joints, pain was assessed upon palpation and synovial thickening, effusion and power Doppler signal (PDS) were scored with standardized methods by US. Associations between inflammatory features and painful joints were analysed using generalized estimated equations to account for patient effects, adjusting for confounders, and presented as odds ratios (ORs) with 95% confidence intervals (95%CI).
Inflammatory US features were seen in (nearly) all patients. The median number (range) of inflammatory joints per patient did not change over time: 9 (0-16) to 9 (2-18). In 18.7% of joints inflammatory features were present at both time points; in 20.5% inflammatory features occurred only at baseline or follow-up. Pain decreased over time: median VAS pain 49-39 mm; median number of painful joints 8-3. Synovial thickening, effusion and PDS were associated with pain upon palpation both at baseline and follow-up: OR 2.9 (1.4, 5.7), 2.7 (1.7, 4.3), 3.6 (2.1, 6.3) and 7.3 (3.2, 16.5), 3.3 (2.3, 4.7), 4.1 (2.1, 7.9). respectively.
In HOA inflammatory US features are stable over time at patient level, but vary on joint level. Pain diminished after 3 months, while associations between painful joints and inflammation seem to increase, emphasizing the multifactorial aetiology of pain.