An ultrasonographic study of enthesis in early psoriatic arthritis patients naive to traditional and biologic DMARDs treatment

The aim of this study was to evaluate the rate of power Doppler ultrasound (PDUS) abnormalities at entheseal sites in patients with early psoriatic arthritis (PsA) naïve to traditional and biologic DMARDs and to compare the PDUS findings with clinical examination. PsA patients with early disease and naïve to traditional and biologic DMARDs were consecutively enrolled in this study. Patients underwent PDUS examination of the following bilateral entheseal sites: common extensor tendon at its insertion at the lateral humeral epicondyle; quadriceps tendon at its insertion at the superior pole of the patella; patellar tendon at its insertion at the tibial tuberosity; medial collateral ligament at its proximal insertion and Achilles tendon at its insertion at the calcaneus. The Leeds enthesitis index (LEI) was used to assess clinical entheseal involvement. Twenty-one early PsA patients completed the clinical and PDUS examinations. Clinical entheseal involvement was found in 9 (42.9 %) and PDUS abnormalities in 20 (95.5 %) of the 21 early PsA patients. Achilles tendon insertion was the site with the major entheseal abnormalities. Active (power Doppler positive) entheseal lesions were found in 4.7, 9.5, 14.3 and 14.3 % of patients at the lateral humeral epicondyle; quadriceps tendon, patellar tendon insertions, and Achilles tendon insertions, respectively. Concordance between clinical (LEI) and PDUS was poor. The present study confirms that PDUS allows detecting structural and inflammatory abnormalities of enthesis in early PsA patients. Our study shows that, in early disease, active abnormalities seem to have a low prevalence.