The Role of Ultrasound in Assessing Hand Joints and Tendons in Psoriatic Arthritis

Introduction: Psoriatic arthritis (PsA) is an inflammatory arthritis, usually involving peripheral joints, associated with cutaneous psoriasis, in the absence of rheumatoid factor and anti-citrullinated protein antibodies. Material and methods: The study included 28 patients diagnosed with psoriatic arthritis according to CASPAR criteria, presenting pain or swelling of the small joints of the hands and wrists, hospitalized in the Department of Rheumatology of the Emergency Clinical County Hospital of Craiova during 2016-2018. Results: In the 28 patients, a total of 840 joints were examined clinically and by ultrasound. From the clinical point of view, out of the total, 32 joints were swollen while 59 joints were tender. Dactylitis was evidenced in 20/280 examined digits upon physical examination. MUS revealed the presence of synovial proliferation in 108/840 sites (12.85%), with grade 1 synovitis in 4 joints (3.7%), grade 2 in 94 joints (87.03%) and grade 3 in 10 joints (9.25%). Out of 280 examined fingers 5.71% presented dactylitis, the third digit being the most commonly targeted. Grade 2 tenosynovitis was found in 40 of the examined tendons, whereas 8 tendons presented with grade 3 tenosynovitis. The most frequently involved were the flexor tendons of the digits (38 out of 40 tendons with inflammatory changes), followed by the extensor carpi ulnaris and flexor carpi radialis tendons. Conclusions: Ultrasound has proven its utility in assessing joint and tendon inflammation to a higher extent that clinically expected. Thus, MUS examination of hand joints may aid the clinician in diagnosing PsA, in evaluating the prognosis and the course of treatment.