Assessment of enthesitis in patients with psoriatic arthritis using clinical examination and ultrasound

Background: Enthesitis is a major feature of psoriatic arthritis.However, clinical assessment of enthesitis is known to lack accuracy and have poor interobserver reliability.Objective: To determine effect of training on clinical assessment of enthesitis and to compare ultrasonography with clinical examination for the detection of entheseal abnormalities.Methods: 20 rheumatologists performed repeated assessment of enthesitis in patients with established psoriatic arthritis before and after a 2-hour training session in standardised enthesitis count according to Leeds Enthesitis Index (LEI) and Spondyloarthritis Research Consortium of Canada Enthesitis Index (SPARCC).Moreover, 20 pa-tients underwent clinical and ultrasonographic examination of entheses to evaluate consensusbased elementary lesions of enthesitis.Results: Training significantly increased Intraclass Correlation Coefficient for LEI from 0.18 to 0.82 and for SPARCC from 0.38 to 0.67.Ultrasound examination showed high associations between hypoechogenicity and increased thickness of the entheses and clinical examination.There was no correlation between erosions and enthesophytes found by ultrasound and clinical assessments.Conclusion: Training in standardised enthesitis scoring systems significantly improved clinical assessments of enthesitis and should be performed before use in daily clinical practice.Ultrasound revealed more advanced stages of enthesitis, such as enthesophytes and erosions, which were not detected with clinical examination.