US Examination of Wrists and Hands: a Comparison Between Rheumatoid Arthritis and Psoriatic Arthritis

Purpose: Very little is known about the possible differences in the involvement of joints and periarticular structures in rheumatoid or psoriatic arthritis (PsA). The main pathological features detected by US in rheumatoid arthritis (RA) are synovitis and bone erosion while, in spondyloarthropathies, entheseal inflammation is the common feature. Tendon involvement is particularly frequent and dactylitis is a typical PsA manifestation. Aim of the study was to investigate the features of wrist and hand involvement in PsA and RA. Method: Bilateral ultrasound (US) examination of the wrist and hand was performed, by the same physician, in a group of subjects affected by RA (n25; F:M20:5; disease duration: 12.5±11 years) and PsA (n25; F:M8:17; disease duration: 8.5±7 years), using a Logiq 9 (General Electrics Medical Systems, Milwaukee, WI) with a linear probe operating at 14 MHz. We examined radiocarpal, intercarpal, metacarpophalangeal, proximal interphalangeal and distal interphalangeal (DIP) joints and flexor and extensor tendons (both in wrist and hand). The patients were recruited on a time-criteria (the last 25 patients for each diagnosis who camed for an outpatient control) from the whole number of subjects referring to the US unit of our Clinic. Results: US examination showed joint wrist synovitis in 10/25 (40) and 12/25 (48) patients (in PsA and RA respectively), hand synovitis in 14/25 (56) and in 16/25 (64) RA and PsA patients respectively. We found DIP joint involvement in only 1 PsA patient, as it was for dactylitis (in a different PsA patient). Bone erosions were present in 10/25 (40) patients, both in RA and PsA group. Tendon involvement was present in the 7/25 (28) and 5/25 (20) in the wrist and 7/25 (28) and 10/25 (40) in the hand respectively. Conclusion: We did not observed significant differences in wrist or hand involvement (both in joint and tendon structures) between RA and PsA patients, except for a more frequent involvement of PIP joints and a slightly higher hand’s tenosynovitis in PsA group