A Systematic Review of the Inclusion of Non-Inflammatory Ultrasonographic Enthesopathy Findings in Enthesitis Scoring Indices

Reliability assessment of the definition of ultrasound enthesitis in SpA: results of a large, multicentre, international, web-based study

OBJECTIVES

To investigate the reliability of the OMERACT US Task Force definition of US enthesitis in SpA.

METHODS

In this web exercise, based on the evaluation of 101 images and 39 clips of the main entheses of the lower limbs, the elementary components included in the OMERACT definition of US enthesitis in SpA (hypoechoic areas, entheseal thickening, power Doppler signal at the enthesis, enthesophytes/calcifications, bone erosions) were assessed by 47 rheumatologists from 37 rheumatology centres in 15 countries. Inter- and intra-observer reliability of the US components of enthesitis was calculated using Light's kappa, Cohen's kappa, Prevalence And Bias Adjusted Kappa (PABAK) and their 95% CIs.

RESULTS

Bone erosions and power Doppler signal at the enthesis showed the highest overall inter-reliability [Light's kappa: 0.77 (0.76-0.78), 0.72 (0.71-0.73), respectively; PABAK: 0.86 (0.86-0.87), 0.73 (0.73-0.74), respectively], followed by enthesophytes/calcifications [Light's kappa: 0.65 (0.64-0.65), PABAK: 0.67 (0.67-0.68)]. This was moderate for entheseal thickening [Light's kappa: 0.41 (0.41-0.42), PABAK: 0.41 (0.40-0.42)], and fair for hypoechoic areas [Light's kappa: 0.37 (0.36-0.38); PABAK: 0.37 (0.37-0.38)]. A similar trend was observed in the intra-reliability exercise, although this was characterized by an overall higher degree of reliability for all US elementary components compared with the inter-observer evaluation.

CONCLUSIONS

The results of this multicentre, international, web-based study show a good reliability of the OMERACT US definition of bone erosions, power Doppler signal at the enthesis and enthesophytes/calcifications. The low reliability of entheseal thickening and hypoechoic areas raises questions about the opportunity to revise the definition of these two major components for the US diagnosis of enthesitis.

Ultrasound Enthesitis in Psoriasis Patients with or without Psoriatic Arthritis, a Cross-Sectional Analysis

Background and objectives: The main objective of the current study was to describe the prevalence of enthesitis at different sites in a group of patients with psoriasis with or without psoriatic arthritis (PsA). Materials and Methods: The study included adult patients with psoriasis who underwent clinical examination, laboratory tests and ultrasound examination of the entheses. The enthesitis ultrasound scores (BUSES, MASEI, GUESS) were evaluated; the presence of OMERACT-defined enthesitis was also recorded for each scan site. Results: The study included 16 (57.1%) patients with PsA and 12 (42.9%) patients with psoriasis, with an increased average body mass index (29.3 kg/m2). Compared to psoriasis patients, PsA patients had a higher prevalence of nail psoriasis (68.8% compared to 33.3%; p = 0.063). There were no significant differences regarding the clinical examination of entheses between patients with psoriasis and patients with PsA (p = 0.459). Ultrasound scores, BUSES, GUESS and MASEI proved to have statistically significant higher median values in PsA patients compared to psoriasis patients. Compared to psoriasis patients, PsA patients had a significantly higher prevalence of OMERACT-defined enthesitis of the quadriceps tendon and inferior patellar ligament (both 81.3% compared to 25.0%, p = 0.003). Clinical examination of the lateral epicondyle and of the superior patellar ligament was consistent with their ultrasound examination (κ = 0.357, p = 0.043, respectively, κ = 0.404, p = 0.008). Conclusions: Clinical enthesitis scores do not differ between psoriasis and PsA patients. All analyzed ultrasound scores are significantly higher in patients with PsA. OMERACT-defined enthesitis has the ability to discriminate sonographic enthesitis between the two subgroups for bilateral quadriceps and inferior patellar tendon enthesitis. Bilateral ultrasound damage of entheses can suggest a PsA diagnosis.

A Narrative Review of the Design of Ultrasound Indices for Detecting Enthesitis

With the increased utilization of musculoskeletal ultrasound in clinical practice, there has been rapid proliferation of publications on sonographic evaluation of enthesitis. This has led to the development of multiple new approaches to scoring sonographic findings in the detection of enthesitis, with variations including entheseal sites and sonographic features that limit cross-study comparisons. Furthermore, despite efforts to standardize the definition of enthesitis, there is still heterogeneity in the sonographic features included in existing ultrasound scores, and additional adjustments are required to distinguish active inflammatory changes from non-inflammatory conditions and to adjust for demographic features associated with increased prevalence of abnormal sonographic findings. This review provides an update on the current landscape of ultrasound scoring systems for enthesitis and emphasizes the importance of future data-based ultrasound scoring systems to improve the distinction between inflammatory and non-inflammatory or degenerative changes of the enthesis.