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

Background/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 particu- larly 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. Methods: Bilateral ultrasound (US) examination of the wrist and hand was performed, by the same physician, in a group of subjects affected by RA (n50; F:M43:7; mean age: 61.312.7 years; disease duration: 112.985.5 months) and PsA (n50; F:M24:26; mean age: 57.412.5 years; disease duration: 100.297.4 months), 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 came 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 37/50 (74) RA and 29/50 (58) PsA patients, hand synovitis in 33/50 (66) and in 36/50 (72) RA and PsA patients respectively. Tendon involvement was present in the 21/50 (42) and 13/50 (26) patients in the wrist and 18/50 (36) in the hand, both in RA and PsA group. Finally, bone erosions were present in 33/50 (66) and 29/50 (58) RA and PsA patients respectively. Conclusion: We did not observed significant differences in wrist or hand involvement (both in joint and tendon structures) between RA and PsA patients, even if a slightly higher frequency of wrist synovitis and tenosynovitis was present in RA group