Objectives: Entheseal involvement is a frequent and distinctive feature of psoriatic arthritis (PsA), and is often under-diagnosed. The aim of the present study is to investigate using ultrasound (US), lower limb entheseal abnormalities in patients with early psoriatic arthritis (ePsA) and to evaluate their correlation with ePsA clinical characteristics.
Methods: Ninety-two ePsA patients (with duration of symptoms less than 1 year), diagnosed according to CASPAR criteria, were consecutively scored with Glasgow Ultrasound Enthesitis Scoring System (GUESS) and Power Doppler (PD) US (My Lab 70 Esaote) of lower limbs entheses (quadriceps, patellar, achilles tendons and plantar fascia). Patients were clinically examined by palpation of lower limbs entheses, Maastricht Ankylosing Spondylitis Enthesitis Index (MASES) and total Psoriasis Area and Severity Index (PASI). Correlations were investigated between GUESS and PD with other ePsA clinical characteristics (duration of symptoms and morning stiffness, pain and fatigue visual analogue scale [VAS], Health Assessment Questionnaire SpA-modified [S-HAQ]).
Results: All patients had GUESS>1 and 40.2% showed positive PD signal on entheses, at a higher percentage than tenderness revealed by clinical examination (29.3%). GUESS and PD did not correlate with MASES, PASI and other clinical characteristics. No significant differences in GUESS and PD were detected between positive or negative findings of MASES and PASI.
Conclusions: US detects subclinical entheseal involvement in ePsA, independently of ePsA clinical examination and symptoms.