Ultrasound description of cortical-entheseal bone remodeling in peripheral entheses of patients with psoriasis and nonspecific musculoskeletal symptoms.

Aims: ultrasound (US) diagnosis of enthesitis is burdened of low specificity, especially when it is performed in patients with psoriasis (PsO) but without clinical psoriatic arthritis (PsA), because of mechanical, dysmetabolic and age-related concurrent enthesopatic changes. We propose a novel US score to quantify the cortical-entheseal bone remodeling burden of several peripheral entheses, aiming to improve the specificity of US for PsA-related enthesitis, and to evaluate its diagnostic value in PsO patients with subsequent diagnosis of psoriatic arthritis (PsO/PsA). Methods: clinical and US data of 119 consecutive patients with moderate/severe PsO and nonspecific musculoskeletal symptoms, were included in this retrospective study. PsO patients underwent a multi-joint US examination and a subsequent rheumatologic visit to evaluate concurrent PsA clinical diagnosis, in a scenario of real clinical practice. The cortical-entheseal bone remodeling has been evaluated with a morphologic gray-scale US score named “CERTUS” (Cortical-Entheseal Remodeling Tuscany Ultrasonographic Score, range 0-36), grading the combination of both enthesophytes and erosions in a semiquantitative scale. A variant of CERTUS, with Power Doppler (PD), was calculated too (CERTUS-PD, range 0-48), scoring PD signals into erosions. The sum of the scores obtained for 12 peripheral entheses was used as global score for statistic aims. The new bone formation at extensor tendon entheses at distal inter-phalangeal (DIP) joints were also recorded. Results: a clinical diagnosis of PsO/PsA was made in 48/119 PsO patients (40.3%), showing older age (p<0.001), higher BMI (p=0.015), prevalence of metabolic syndrome (p=0.014) and smoking habit (p<0.001). CERTUS (AUROC 0.814) showed a highest specificity cut-off=11 (sensitivity 41.4%, specificity 100%), whereas CERTUS-PD (AUROC 0.828) showed a highest specificity cut-off=13 (sensitivity 37.9%, specificity 100%). CERTUS and CERTUS-PD correlated with both other validated US scores as Belgrade Ultrasound Enthesitis Score (BUSES) (p<0.001), DACTylitis glObal Sonographic (DACTOS) score (p=0.05 and p=0.031 respectively), amount of synovitis (p=0.036 and p=0.04 respectively), enthesitis (p<0.001) and entheseal new bone formation on DIP joints (p=0.029 and p=0.031 respectively). Conclusions: the scoring system named CERTUS (and its variant with PD) is a quick tool to quantify cortico-entheseal bone remodeling burden in PsO patients, improving the specificity of US to diagnose patients with subclinical PsA-related enthesitis.