The incremental value of ultrasound in detection of subclinical peripheral enthesitis in patients with spondyloarthritis

Inflammatory enthesitis is a hallmark in Spondyloarthritis (SpA). It is detected by clinical examination but lacks sensitivity and reliability. Ultrasonography (US) is more accurate in detecting enthesitis. To evaluate the value of US in diagnosis of enthesopathy in SpA and assess its relation compared to clinical assessment. Thirty-one SpA patients were subjected to history-taking, clinical examination, laboratory investigations, clinical and US assessment of the same entheseal points. The patients mean age was 41.2 ± 2.4 years (28–68 years); 23 males and 8 females. The mean disease duration was 10.4 ± 3.3 years (2 months to 20 years). 12 cases had psoriatic arthritis (PsA), 12 ankylosing spondylitis (AS) and 7 had reactive arthritis (ReA). Most commonly affected entheses in lower limbs were Achilles tendons (right; 70% and left; 80%), while in the upper limbs were supraspinatus tendons (right; 65% and left; 35%). A significant difference was found between clinical and US examination of enthesitis as 19% of examined entheses were abnormal clinically, while 57% with US. Significant agreement was found between clinical and ultrasound examination in detection of enthesitis at supraspinatus with maximum odd ratios for calcifications 72 and erosions 16. Sensitivity of US was 91.9%, while specificity was 83.7%. Ultrasonography is superior to clinical examination in detection of enthesitis in SpA patients with good sensitivity and specificity. Enthesitis is common in upper limbs as it is in lower limbs; pathological findings and predictive values of calcifications and erosions were high at entheses of upper limbs especially supraspinatus.